Working tools

The Santa Clara County Planting Calendar

Eighty crops, 149 planting windows, worked out from this county's own climate record rather than copied from a national chart. Every date will show you how it was reached.

Three things about growing here

Spring opens in mid-January, and that's about mud rather than cold. Our soil never falls below the germination minimum for a hardy crop. What holds you back in January is workable ground, not temperature.

You sow the autumn garden into the heat, not out of it. The hottest stretch of our year is late August, not July. August and September sowings need shade and steady water to come up at all. That is the opposite of how most gardening advice reads, because most of it is written for somewhere else.

The autumn deadline is light, not frost. From late November to late January the day runs under ten hours and growth all but stops. A hardy crop sits out that stretch and finishes as the light returns. A tender one has to be done before it starts. Frost barely enters into it here: we get 307 frost-free days, and the last freeze lands in early February.

Search crops

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Arugula

Eruca vesicaria subsp. sativa Brassicaceae · hardy

Planting windows for Arugula
Spring sow	Jan 15 – May 30	Sow Jan 15 to May 30. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 40F (Oregon State University Extension minimum for cabbage). Latest date is where the crop's heat-and-light budget (30d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 30-day subtraction would give.
Fall sow	Aug 5 – Oct 21	Sow Aug 5 to Oct 21. It's hardy enough to sit out the short days and finish as light returns in late January. Why this date? Latest date is where the crop's heat-and-light budget still finishes (30d nominal, 3.00x here) before growth resumes Jan 22. Hardy enough to hold in the field through the 10-hour days and finish as light returns. The window opens as the late-August heat peak passes; in Santa Clara County you sow into heat, not out of it.

Check it yourself: sow once soil at 2 in reads 40°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

Cornell Garden-Based Learning. (n.d.). Arugula. https://gardening.cals.cornell.edu/garden-guidance/foodgarden/vegetable-growing-guides/arugula/

Beet (Table Beet)

Beta vulgaris subsp. vulgaris Chenopodiaceae · hardy

Planting windows for Beet (Table Beet)
Spring sow	Jan 15 – May 7	Sow Jan 15 to May 7. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 40F (Oregon State University Extension minimum for beet). Latest date is where the crop's heat-and-light budget (60d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 60-day subtraction would give.
Fall sow	Aug 5 – Sep 14	Sow Aug 5 to Sep 14. It's hardy enough to sit out the short days and finish as light returns in late January. Why this date? Latest date is where the crop's heat-and-light budget still finishes (60d nominal, 2.08x here) before growth resumes Jan 22. Hardy enough to hold in the field through the 10-hour days and finish as light returns. The window opens as the late-August heat peak passes; in Santa Clara County you sow into heat, not out of it.

Check it yourself: sow once soil at 2 in reads 40°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

Cornell University. (n.d.). Explore Cornell — Home gardening: Beet growing guide. http://www.gardening.cornell.edu/homegardening/scene18f3.html; University of Minnesota Extension. (n.d.). Planting the vegetable garden. https://extension.umn.edu/planting-and-growing-guides/planting-vegetable-garden; Oregon State University Extension Service. (n.d.). Grow your own root vegetables. https://extension.oregonstate.edu/gardening/techniques/grow-your-own-root-vegetables; Cornell Vegetables. (n.d.). Cercospora leaf spot of table beet. https://www.vegetables.cornell.edu/pest-management/disease-factsheets/cercospora-leaf-spot-of-table-beet/; Penn State Extension. (n.d.). Cercospora leaf spot on table beets. https://extension.psu.edu/cercospora-leaf-spot-on-table-beets; Utah State University Extension. (n.d.). Beet curly top virus. https://extension.usu.edu/pests/ipm/notes_ag/veg-beet-curly-top-virus; University of Maryland Extension. (n.d.). Beet and spinach leafminers. https://extension.umd.edu/resource/beet-and-spinach-leafminers

Bok Choy

Brassica rapa subsp. chinensis Brassicaceae · half-hardy

Planting windows for Bok Choy
Spring sow	Jan 15 – May 13	Sow Jan 15 to May 13. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 40F (Oregon State University Extension minimum for cabbage). Latest date is where the crop's heat-and-light budget (52d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 52-day subtraction would give.
Set out fall transplants	Jul 29 – Sep 14	Set transplants out Jul 29 to Sep 14. Later than that and it won't size up before the light goes in late November. Why this date? Latest date is where the crop's heat-and-light budget still finishes (52d nominal, 1.31x here) before daylength drops under 10h on Nov 23.
Sow for those transplants	Jun 17 – Aug 10	Raising your own? Sow Jun 17 to Aug 10, about five weeks before they go out. Buying starts is a perfectly good call here. Why this date? Five to six weeks before setting out. Or buy starts, which is what most growers do for the fall brassicas.

Check it yourself: sow once soil at 2 in reads 40°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing Chinese cabbage and bok choy. https://extension.umn.edu/vegetables/growing-chinese-cabbage-and-bok-choy; Cornell Cooperative Extension. (n.d.). Bok choy. http://www.gardening.cornell.edu/homegardening/scene0bdf.html

Broccoli

Brassica oleracea var. italica Brassicaceae · hardy

Planting windows for Broccoli
Spring sow	Jan 15 – Apr 27	Sow Jan 15 to Apr 27. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 40F (Oregon State University Extension minimum for cabbage). Latest date is where the crop's heat-and-light budget (67d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 67-day subtraction would give.
Set out fall transplants	Jul 29 – Sep 7	Set transplants out Jul 29 to Sep 7. It'll hold through the short days and finish as light returns in late January. Why this date? Latest date is where the crop's heat-and-light budget still finishes (67d nominal, 2.03x here) before growth resumes Jan 22. Hardy enough to hold through the 10-hour days.
Sow for those transplants	Jun 17 – Aug 3	Raising your own? Sow Jun 17 to Aug 3, about five weeks before they go out. Buying starts is a perfectly good call here. Why this date? Five to six weeks before setting out. Or buy starts, which is what most growers do for the fall brassicas.

Check it yourself: sow once soil at 2 in reads 40°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing broccoli. https://extension.umn.edu/vegetables/growing-broccoli; Cornell Cooperative Extension. (n.d.). Broccoli. http://www.gardening.cornell.edu/homegardening/scene91d8.html

Carrot

Daucus carota subsp. sativus Apiaceae · hardy

Planting windows for Carrot
Spring sow	Jan 15 – May 4	Sow Jan 15 to May 4. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 40F (Oregon State University Extension minimum for carrot). Latest date is where the crop's heat-and-light budget (62d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 62-day subtraction would give.
Fall sow	Aug 5 – Sep 12	Sow Aug 5 to Sep 12. It's hardy enough to sit out the short days and finish as light returns in late January. Why this date? Latest date is where the crop's heat-and-light budget still finishes (62d nominal, 2.06x here) before growth resumes Jan 22. Hardy enough to hold in the field through the 10-hour days and finish as light returns. The window opens as the late-August heat peak passes; in Santa Clara County you sow into heat, not out of it.

Check it yourself: sow once soil at 2 in reads 40°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing carrots and parsnips. https://extension.umn.edu/vegetables/growing-carrots-and-parsnips; Michigan State University Extension. (n.d.). How to grow carrots. https://www.canr.msu.edu/resources/how_to_grow_carrots; University of Maryland Extension. (n.d.). Growing carrots in the home garden. https://extension.umd.edu/resource/growing-carrots-home-garden

Daikon

Raphanus sativus var. longipinnatus Brassicaceae · hardy

Planting windows for Daikon
Spring sow	Jan 15 – May 7	Sow Jan 15 to May 7. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 40F (Oregon State University Extension minimum for radish). Latest date is where the crop's heat-and-light budget (60d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 60-day subtraction would give.
Fall sow	Aug 5 – Sep 14	Sow Aug 5 to Sep 14. It's hardy enough to sit out the short days and finish as light returns in late January. Why this date? Latest date is where the crop's heat-and-light budget still finishes (60d nominal, 2.08x here) before growth resumes Jan 22. Hardy enough to hold in the field through the 10-hour days and finish as light returns. The window opens as the late-August heat peak passes; in Santa Clara County you sow into heat, not out of it.

Check it yourself: sow once soil at 2 in reads 40°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

Cornell Cooperative Extension. (n.d.). Radish growing guide. https://www.gardening.cornell.edu/homegardening/scenef99a.html; University of Hawaii at Manoa CTAHR. (n.d.). Daikon production. https://www.ctahr.hawaii.edu/oc/freepubs/; Oregon State University Extension Service. (n.d.). Growing radishes in your home garden. https://extension.oregonstate.edu/gardening/vegetables/growing-radishes-your-home-garden

Dill

Anethum graveolens Apiaceae · half-hardy

Planting windows for Dill
Spring sow	Jan 15 – May 15	Sow Jan 15 to May 15. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 40F (Oregon State University Extension minimum for parsley). Latest date is where the crop's heat-and-light budget (50d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 50-day subtraction would give.
Fall sow	Aug 5 – Sep 16	Sow Aug 5 to Sep 16. Later than that and it can't reach size before the light goes in late November. Why this date? Latest date is where the crop's heat-and-light budget still finishes (50d nominal, 1.32x here) before daylength drops under 10h on Nov 23. Half-hardy, so it must arrive nearly finished. The window opens as the late-August heat peak passes; in Santa Clara County you sow into heat, not out of it.

Check it yourself: sow once soil at 2 in reads 40°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing dill. https://extension.umn.edu/vegetables/growing-dill; Oregon State University Extension. (n.d.). Carrot rust fly biology and management. https://extension.oregonstate.edu/crop-production/vegetables/carrot-rust-fly-biology-management

Kale (curly)

Brassica oleracea var. acephala Brassicaceae · very-hardy

Planting windows for Kale (curly)
Spring sow	Jan 15 – May 4	Sow Jan 15 to May 4. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 40F (Oregon State University Extension minimum for cabbage). Latest date is where the crop's heat-and-light budget (62d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 62-day subtraction would give.
Set out fall transplants	Jul 29 – Sep 12	Set transplants out Jul 29 to Sep 12. It'll hold through the short days and finish as light returns in late January. Why this date? Latest date is where the crop's heat-and-light budget still finishes (62d nominal, 2.06x here) before growth resumes Jan 22. Very-hardy enough to hold through the 10-hour days.
Sow for those transplants	Jun 17 – Aug 8	Raising your own? Sow Jun 17 to Aug 8, about five weeks before they go out. Buying starts is a perfectly good call here. Why this date? Five to six weeks before setting out. Or buy starts, which is what most growers do for the fall brassicas.

Check it yourself: sow once soil at 2 in reads 40°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing collards and kale. https://extension.umn.edu/vegetables/growing-collards-and-kale; Cornell Cooperative Extension. (n.d.). Kale. http://www.gardening.cornell.edu/homegardening/scene57dc.html

Kohlrabi

Brassica oleracea var. gongylodes Brassicaceae · half-hardy

Planting windows for Kohlrabi
Spring sow	Jan 15 – May 17	Sow Jan 15 to May 17. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 40F (Oregon State University Extension minimum for cabbage). Latest date is where the crop's heat-and-light budget (47d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 47-day subtraction would give.
Set out fall transplants	Jul 29 – Sep 19	Set transplants out Jul 29 to Sep 19. Later than that and it won't size up before the light goes in late November. Why this date? Latest date is where the crop's heat-and-light budget still finishes (47d nominal, 1.32x here) before daylength drops under 10h on Nov 23.
Sow for those transplants	Jun 17 – Aug 15	Raising your own? Sow Jun 17 to Aug 15, about five weeks before they go out. Buying starts is a perfectly good call here. Why this date? Five to six weeks before setting out. Or buy starts, which is what most growers do for the fall brassicas.

Check it yourself: sow once soil at 2 in reads 40°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing kohlrabi. https://extension.umn.edu/vegetables/growing-kohlrabi; Cornell Cooperative Extension. (n.d.). Kohlrabi. http://www.gardening.cornell.edu/homegardening/scene1357.html

Leaf Lettuce (loose-leaf)

Lactuca sativa Asteraceae · half-hardy

Planting windows for Leaf Lettuce (loose-leaf)
Spring sow	Jan 15 – May 17	Sow Jan 15 to May 17. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 35F (Oregon State University Extension minimum for lettuce). Latest date is where the crop's heat-and-light budget (47d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 47-day subtraction would give.
Fall sow	Aug 5 – Sep 19	Sow Aug 5 to Sep 19. Later than that and it can't reach size before the light goes in late November. Why this date? Latest date is where the crop's heat-and-light budget still finishes (47d nominal, 1.32x here) before daylength drops under 10h on Nov 23. Half-hardy, so it must arrive nearly finished. The window opens as the late-August heat peak passes; in Santa Clara County you sow into heat, not out of it.

Check it yourself: sow once soil at 2 in reads 35°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing lettuce, endive and radicchio in home gardens. https://extension.umn.edu/vegetables/growing-lettuce-endive-and-radicchio

Mustard Greens

Brassica juncea Brassicaceae · half-hardy to hardy

Planting windows for Mustard Greens
Spring sow	Jan 15 – May 22	Sow Jan 15 to May 22. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 40F (Oregon State University Extension minimum for cabbage). Latest date is where the crop's heat-and-light budget (40d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 40-day subtraction would give.
Fall sow	Aug 5 – Sep 27	Sow Aug 5 to Sep 27. Later than that and it can't reach size before the light goes in late November. Why this date? Latest date is where the crop's heat-and-light budget still finishes (40d nominal, 1.43x here) before daylength drops under 10h on Nov 23. Half-hardy, so it must arrive nearly finished. The window opens as the late-August heat peak passes; in Santa Clara County you sow into heat, not out of it.

Check it yourself: sow once soil at 2 in reads 40°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

Cornell Cooperative Extension. (n.d.). Mustard greens. http://www.gardening.cornell.edu/homegardening/scene2b9a.html

Radish (round red salad)

Raphanus sativus Brassicaceae · hardy

Planting windows for Radish (round red salad)
Spring sow	Jan 15 – May 31	Sow Jan 15 to May 31. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 40F (Oregon State University Extension minimum for radish). Latest date is where the crop's heat-and-light budget (28d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 28-day subtraction would give.
Fall sow	Aug 5 – Oct 24	Sow Aug 5 to Oct 24. It's hardy enough to sit out the short days and finish as light returns in late January. Why this date? Latest date is where the crop's heat-and-light budget still finishes (28d nominal, 3.11x here) before growth resumes Jan 22. Hardy enough to hold in the field through the 10-hour days and finish as light returns. The window opens as the late-August heat peak passes; in Santa Clara County you sow into heat, not out of it.

Check it yourself: sow once soil at 2 in reads 40°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing radishes. https://extension.umn.edu/vegetables/growing-radishes; Cornell Cooperative Extension. (n.d.). Radish. http://www.gardening.cornell.edu/homegardening/scene341b.html

Snap Pea

Pisum sativum var. macrocarpon Fabaceae · hardy

Planting windows for Snap Pea
Spring sow	Jan 15 – Apr 30	Sow Jan 15 to Apr 30. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 40F (Oregon State University Extension minimum for pea). Latest date is where the crop's heat-and-light budget (65d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 65-day subtraction would give.
Fall sow	Aug 5 – Sep 9	Sow Aug 5 to Sep 9. It's hardy enough to sit out the short days and finish as light returns in late January. Why this date? Latest date is where the crop's heat-and-light budget still finishes (65d nominal, 2.05x here) before growth resumes Jan 22. Hardy enough to hold in the field through the 10-hour days and finish as light returns. The window opens as the late-August heat peak passes; in Santa Clara County you sow into heat, not out of it.

Check it yourself: sow once soil at 2 in reads 40°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

Snow Pea

Pisum sativum var. macrocarpon Fabaceae · hardy

Planting windows for Snow Pea
Spring sow	Jan 15 – May 4	Sow Jan 15 to May 4. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 40F (Oregon State University Extension minimum for pea). Latest date is where the crop's heat-and-light budget (62d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 62-day subtraction would give.
Fall sow	Aug 5 – Sep 12	Sow Aug 5 to Sep 12. It's hardy enough to sit out the short days and finish as light returns in late January. Why this date? Latest date is where the crop's heat-and-light budget still finishes (62d nominal, 2.06x here) before growth resumes Jan 22. Hardy enough to hold in the field through the 10-hour days and finish as light returns. The window opens as the late-August heat peak passes; in Santa Clara County you sow into heat, not out of it.

Check it yourself: sow once soil at 2 in reads 40°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing peas. https://extension.umn.edu/vegetables/growing-peas; Penn State Extension. (n.d.). A gardener's guide to peas. https://extension.psu.edu/a-gardeners-guide-to-peas; Cornell Cooperative Extension. (n.d.). Peas. http://www.gardening.cornell.edu/homegardening/scene9697.html

Spinach

Spinacia oleracea Chenopodiaceae · very-hardy

Planting windows for Spinach
Spring sow	Jan 15 – May 11	Sow Jan 15 to May 11. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 35F (Oregon State University Extension minimum for spinach). Latest date is where the crop's heat-and-light budget (55d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 55-day subtraction would give.
Fall sow	Aug 5 – Sep 20	Sow Aug 5 to Sep 20. It's hardy enough to sit out the short days and finish as light returns in late January. Why this date? Latest date is where the crop's heat-and-light budget still finishes (55d nominal, 2.20x here) before growth resumes Jan 22. Very-hardy enough to hold in the field through the 10-hour days and finish as light returns. The window opens as the late-August heat peak passes; in Santa Clara County you sow into heat, not out of it.

Check it yourself: sow once soil at 2 in reads 35°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing spinach and Swiss chard in home gardens. https://extension.umn.edu/vegetables/growing-spinach-and-swiss-chard; Cornell University. (n.d.). Explore Cornell — Home gardening: Spinach growing guide. http://www.gardening.cornell.edu/homegardening/scene4c19.html; Cornell Vegetables. (n.d.). Spinach. https://www.vegetables.cornell.edu/crops/spinach/; Cornell Vegetables. (n.d.). Spinach downy mildew fact sheet. https://www.vegetables.cornell.edu/pest-management/disease-factsheets/spinach-downy-mildew/; University of Maryland Extension. (n.d.). Beet and spinach leafminers. https://extension.umd.edu/resource/beet-and-spinach-leafminers

Swiss Chard

Beta vulgaris subsp. cicla Chenopodiaceae · very-hardy

Planting windows for Swiss Chard
Spring sow	Jan 15 – May 11	Sow Jan 15 to May 11. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 40F (Oregon State University Extension minimum for chard). Latest date is where the crop's heat-and-light budget (55d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 55-day subtraction would give.
Fall sow	Aug 5 – Sep 20	Sow Aug 5 to Sep 20. It's hardy enough to sit out the short days and finish as light returns in late January. Why this date? Latest date is where the crop's heat-and-light budget still finishes (55d nominal, 2.20x here) before growth resumes Jan 22. Very-hardy enough to hold in the field through the 10-hour days and finish as light returns. The window opens as the late-August heat peak passes; in Santa Clara County you sow into heat, not out of it.

Check it yourself: sow once soil at 2 in reads 40°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing spinach and Swiss chard in home gardens. https://extension.umn.edu/vegetables/growing-spinach-and-swiss-chard; Oregon State University Extension Service. (n.d.). Grow your own root vegetables. https://extension.oregonstate.edu/gardening/techniques/grow-your-own-root-vegetables; UMass Extension. (n.d.). Cercospora leaf spot of Swiss chard, beets, and spinach. https://ag.umass.edu/vegetable/fact-sheets/cercospora-leaf-spot-of-swiss-chard-beets-spinach; Cornell Vegetables. (n.d.). Cercospora leaf spot of table beet. https://www.vegetables.cornell.edu/pest-management/disease-factsheets/cercospora-leaf-spot-of-table-beet/; University of Maryland Extension. (n.d.). Beet and spinach leafminers. https://extension.umd.edu/resource/beet-and-spinach-leafminers

Turnip

Brassica rapa subsp. rapa Brassicaceae · hardy

Planting windows for Turnip
Spring sow	Jan 15 – May 19	Sow Jan 15 to May 19. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 40F (Oregon State University Extension minimum for turnip). Latest date is where the crop's heat-and-light budget (45d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 45-day subtraction would give.
Fall sow	Aug 5 – Oct 2	Sow Aug 5 to Oct 2. It's hardy enough to sit out the short days and finish as light returns in late January. Why this date? Latest date is where the crop's heat-and-light budget still finishes (45d nominal, 2.49x here) before growth resumes Jan 22. Hardy enough to hold in the field through the 10-hour days and finish as light returns. The window opens as the late-August heat peak passes; in Santa Clara County you sow into heat, not out of it.

Check it yourself: sow once soil at 2 in reads 40°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing turnips and rutabagas. https://extension.umn.edu/vegetables/growing-turnips-and-rutabagas; Cornell Cooperative Extension. (n.d.). Turnip. http://www.gardening.cornell.edu/homegardening/scene0f7d.html

Bulb Onion

Allium cepa Amaryllidaceae · hardy

Planting windows for Bulb Onion
Sow to overwinter	Oct 1 – Nov 15	Sow Oct 1 to Nov 15 and let it stand through winter. It ticks over slowly through the short days and finishes in spring. Why this date? Maturity exceeds the short-day deadline, so this crop is sown in autumn, holds through the 10-hour days, and finishes in spring.
Harvest	Apr 15 – Jun 15	Harvest Apr 15 to Jun 15. Why this date? Spring finish once daylength and temperature return.

Check it yourself: sow once soil at 2 in reads 35°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Onions bulb according to daylength. At our latitude choose intermediate-day varieties; long-day types won't bulb reliably here.

Sources

University of Minnesota Extension. (n.d.). Growing onions in home gardens. https://extension.umn.edu/vegetables/growing-onions; Cornell Garden-Based Learning. (n.d.). Onion / scallion growing guide. http://www.gardening.cornell.edu/homegardening/scene4983.html; Johnny's Selected Seeds. (n.d.). Onion bulbing daylength latitude map. https://www.johnnyseeds.com/growers-library/vegetables/onions/onion-bulbing-daylength-latitude-map.html

Fava Bean

Vicia faba Fabaceae · very-hardy

Planting windows for Fava Bean
Sow to overwinter	Oct 1 – Nov 15	Sow Oct 1 to Nov 15 and let it stand through winter. It ticks over slowly through the short days and finishes in spring. Why this date? Maturity exceeds the short-day deadline, so this crop is sown in autumn, holds through the 10-hour days, and finishes in spring.
Harvest	Apr 15 – Jun 15	Harvest Apr 15 to Jun 15. Why this date? Spring finish once daylength and temperature return.

Check it yourself: sow once soil at 2 in reads 40°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

Oregon State University Horticulture. (n.d.). Beans, fava. https://horticulture.oregonstate.edu/oregon-vegetables/beans-fava; Sattell, R., Dick, R., & McGrath, D. (n.d.). Fava bean (Vicia faba L.) [OSU EM 8697]. Oregon State University Extension. https://ir.library.oregonstate.edu/downloads/1g05fb98c; Cornell University. (n.d.). Faba bean / favabean / broadbean / horsebean. Cornell World Crops. https://blogs.cornell.edu/worldcrops/crops/crops-alphabetical/fababean-favabean-broadbean-horsebean/

Amaranth / Callaloo (leaf type)

Amaranthus tricolor Chenopodiaceae · tender

Planting windows for Amaranth / Callaloo (leaf type)
Direct sow	May 5 – Aug 8	Sow May 5 to Aug 8. Past that there isn't enough warm weather left to fill out a crop. Why this date? Measured soil temperature reaches 65F (practical stand floor; absolute minimum 65F per dataset germination range (low end)) and nights hold above 48F. Latest date leaves 45d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 65°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

North Carolina State University Extension. (n.d.). Amaranthus tricolor. NCSU Plant Toolbox. https://plants.ces.ncsu.edu/plants/amaranthus-tricolor/; North Carolina State University Extension. (n.d.). Callaloo — Amaranthus tricolor. NCSU Plant Toolbox. https://plants.ces.ncsu.edu/plants/amaranthus-tricolor/common-name/callaloo/; Liu, G., Simonne, E., Li, Y., Wang, Q., & Sui, J. (2021). HS1407: Production Guide of Vegetable Amaranth for Florida. UF/IFAS Extension. https://edis.ifas.ufl.edu/publication/HS1407; Penn State Extension. (n.d.). Vegetable gardening. https://extension.psu.edu/vegetable-gardening

Bitter Melon

Momordica charantia Cucurbitaceae · tender

Planting windows for Bitter Melon
Start indoors	May 29 – Jun 12	Start seed indoors May 29 to Jun 12. Why this date? 4-6 weeks before the transplant-out date.
Direct sow	Jul 10 – Jul 24	Sow Jul 10 to Jul 24. Past that there isn't enough warm weather left to fill out a crop. Why this date? Measured soil temperature reaches 75F (practical stand floor; absolute minimum 75F per dataset germination range (low end)) and nights hold above 48F. Latest date leaves 90d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 75°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

This one only just fits our summer. Pick the fastest-maturing variety you can find.

Sources

University of Minnesota Extension. (n.d.). Growing staple vegetables from around the world. https://extension.umn.edu/vegetables/growing-staple-vegetables-around-world-minnesota; University of Hawaii CTAHR. (n.d.). Bitter melon. https://gms.ctahr.hawaii.edu/gs/handler/getmedia.ashx?moid=3153&dt=3&g=12

Bush Bean

Phaseolus vulgaris Fabaceae · tender

Planting windows for Bush Bean
Direct sow	Apr 12 – Jul 27	Sow Apr 12 to Jul 27. Past that there isn't enough warm weather left to fill out a crop. Why this date? Measured soil temperature reaches 60F (practical stand floor; absolute minimum 60F per Oregon State University Extension minimum for bean) and nights hold above 48F. Latest date leaves 57d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 60°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing beans in home gardens. https://extension.umn.edu/vegetables/growing-beans; Penn State Extension. (n.d.). Growing snap beans in the home garden. https://extension.psu.edu/growing-snap-beans-in-the-home-garden; Cornell Cooperative Extension. (n.d.). Bush beans. http://www.gardening.cornell.edu/homegardening/scenef57c.html

Butternut Squash

Cucurbita moschata Cucurbitaceae · tender

Planting windows for Butternut Squash
Start indoors	Mar 15 – Mar 29	Start seed indoors Mar 15 to Mar 29. Why this date? 2-4 weeks before the transplant-out date.
Direct sow	Apr 12 – Jun 14	Sow Apr 12 to Jun 14. Past that there isn't enough warm weather left to fill out a crop. Why this date? Measured soil temperature reaches 60F (practical stand floor; absolute minimum 60F per Oregon State University Extension minimum for squash) and nights hold above 48F. Latest date leaves 100d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 60°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing winter squash and pumpkins. https://extension.umn.edu/vegetables/pumpkins-and-winter-squash; Oregon State University Extension Service. (n.d.). Growing pumpkins and winter squash in the home garden. https://extension.oregonstate.edu/news/plan-now-harvest-store-pumpkins-winter-squash

Cabbage (green head)

Brassica oleracea var. capitata Brassicaceae · hardy

Planting windows for Cabbage (green head)
Spring sow	Jan 15 – Apr 3	Sow Jan 15 to Apr 3. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 40F (Oregon State University Extension minimum for cabbage). Latest date is where the crop's heat-and-light budget (80d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 80-day subtraction would give.
Set out fall transplants	Jul 29 – Aug 23	Set transplants out Jul 29 to Aug 23. It'll hold through the short days and finish as light returns in late January. Why this date? Latest date is where the crop's heat-and-light budget still finishes (80d nominal, 1.81x here) before growth resumes Jan 22. Hardy enough to hold through the 10-hour days.
Sow for those transplants	Jun 17 – Jul 19	Raising your own? Sow Jun 17 to Jul 19, about five weeks before they go out. Buying starts is a perfectly good call here. Why this date? Five to six weeks before setting out. Or buy starts, which is what most growers do for the fall brassicas.

Check it yourself: sow once soil at 2 in reads 40°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing cabbage. https://extension.umn.edu/vegetables/growing-cabbage; Cornell Cooperative Extension. (n.d.). Cabbage. http://www.gardening.cornell.edu/homegardening/scene5fdd.html

Calabaza

Cucurbita moschata Cucurbitaceae · tender

Planting windows for Calabaza
Start indoors	Mar 15 – Mar 29	Start seed indoors Mar 15 to Mar 29. Why this date? 2-4 weeks before the transplant-out date.
Direct sow	Apr 12 – Jun 7	Sow Apr 12 to Jun 7. Past that there isn't enough warm weather left to fill out a crop. Why this date? Measured soil temperature reaches 60F (practical stand floor; absolute minimum 60F per Oregon State University Extension minimum for squash) and nights hold above 48F. Latest date leaves 107d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 60°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Florida IFAS Extension. (n.d.). Calabaza (tropical pumpkin) production in Florida. https://edis.ifas.ufl.edu/publication/HS124; Cornell Cooperative Extension. (n.d.). Winter squash. https://www.vegetables.cornell.edu/crops/winter-squash/; University of Puerto Rico Agricultural Experiment Station. (n.d.). Calabaza production guide.

Cantaloupe / Muskmelon

Cucumis melo var. reticulatus Cucurbitaceae · tender

Planting windows for Cantaloupe / Muskmelon
Start indoors	Mar 15 – Mar 22	Start seed indoors Mar 15 to Mar 22. Why this date? 3-4 weeks before the transplant-out date.
Direct sow	Apr 12 – Jun 27	Sow Apr 12 to Jun 27. Past that there isn't enough warm weather left to fill out a crop. Why this date? Measured soil temperature reaches 60F (practical stand floor; absolute minimum 60F per Oregon State University Extension minimum for muskmelon) and nights hold above 48F. Latest date leaves 87d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 60°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing melons. https://extension.umn.edu/fruit/growing-melons-home-garden; Penn State Extension. (n.d.). Cantaloupe production. https://extension.psu.edu/cantaloupe-muskmelon-production

Cauliflower

Brassica oleracea var. botrytis Brassicaceae · hardy

Planting windows for Cauliflower
Spring sow	Jan 15 – Apr 9	Sow Jan 15 to Apr 9. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 40F (Oregon State University Extension minimum for cauliflower). Latest date is where the crop's heat-and-light budget (77d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 77-day subtraction would give.
Set out fall transplants	Jul 29 – Aug 27	Set transplants out Jul 29 to Aug 27. It'll hold through the short days and finish as light returns in late January. Why this date? Latest date is where the crop's heat-and-light budget still finishes (77d nominal, 1.90x here) before growth resumes Jan 22. Hardy enough to hold through the 10-hour days.
Sow for those transplants	Jun 17 – Jul 23	Raising your own? Sow Jun 17 to Jul 23, about five weeks before they go out. Buying starts is a perfectly good call here. Why this date? Five to six weeks before setting out. Or buy starts, which is what most growers do for the fall brassicas.

Check it yourself: sow once soil at 2 in reads 40°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing cauliflower. https://extension.umn.edu/vegetables/growing-cauliflower; Cornell Cooperative Extension. (n.d.). Cauliflower. http://www.gardening.cornell.edu/homegardening/scene595b.html

Celery

Apium graveolens var. dulce Apiaceae · half-hardy

Planting windows for Celery
Spring sow	Jan 15 – Mar 8	Sow Jan 15 to Mar 8. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 40F (Oregon State University Extension minimum for parsley). Latest date is where the crop's heat-and-light budget (105d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 105-day subtraction would give.
Set out transplants (main season)	Jun 21 – Jul 21	Set transplants out Jun 21 to Jul 21, for a crop that finishes into the cool months. Why this date? Latest date is where the crop's heat-and-light budget still finishes (105d nominal, 1.18x here) before daylength drops under 10h on Nov 23.
Sow for those transplants	May 10 – Jun 16	Raising your own? Sow May 10 to Jun 16, about five weeks before they go out. Buying starts is a perfectly good call here. Why this date? Five to six weeks before setting out. Or buy starts, which is what most growers do for the fall brassicas.

Check it yourself: sow once soil at 2 in reads 40°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

Cornell Cooperative Extension. (n.d.). Celery. http://www.gardening.cornell.edu/homegardening/scene810e.html; Michigan State University Extension. (n.d.). Celery commercial vegetable recommendations. https://www.canr.msu.edu/resources/celery_commercial_vegetable_recommendations_e1308

Chayote / Mirliton / Christophine

Sechium edule Cucurbitaceae · tender

Planting windows for Chayote / Mirliton / Christophine
Direct sow	Jun 5 – Jun 19	Sow Jun 5 to Jun 19. Past that there isn't enough warm weather left to fill out a crop. Why this date? Measured soil temperature reaches 70F (practical stand floor; absolute minimum 70F per dataset germination range (low end)) and nights hold above 48F. Latest date leaves 150d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 70°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

This one only just fits our summer. Pick the fastest-maturing variety you can find.

Sources

University of Florida IFAS Extension. (n.d.). Chayote — Sechium edule. https://edis.ifas.ufl.edu/publication/MV055; University of Hawaii at Manoa CTAHR. (n.d.). Chayote production guide. https://www.ctahr.hawaii.edu/oc/freepubs/; LSU AgCenter. (n.d.). Mirliton production. https://www.lsuagcenter.com/

Chicory / Radicchio

Cichorium intybus Asteraceae · hardy

Planting windows for Chicory / Radicchio
Spring sow	Jan 15 – Apr 3	Sow Jan 15 to Apr 3. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 35F (Oregon State University Extension minimum for lettuce). Latest date is where the crop's heat-and-light budget (80d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 80-day subtraction would give.
Set out fall transplants	Jul 29 – Aug 23	Set transplants out Jul 29 to Aug 23. It'll hold through the short days and finish as light returns in late January. Why this date? Latest date is where the crop's heat-and-light budget still finishes (80d nominal, 1.81x here) before growth resumes Jan 22. Hardy enough to hold through the 10-hour days.
Sow for those transplants	Jun 17 – Jul 19	Raising your own? Sow Jun 17 to Jul 19, about five weeks before they go out. Buying starts is a perfectly good call here. Why this date? Five to six weeks before setting out. Or buy starts, which is what most growers do for the fall brassicas.

Check it yourself: sow once soil at 2 in reads 35°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing lettuce, endive and radicchio in home gardens. https://extension.umn.edu/vegetables/growing-lettuce-endive-and-radicchio; University of Minnesota Extension Fruit & Vegetable IPM. (2023). Forcing chicories: An opportunity for diversifying season extension on Minnesota vegetable farms. https://blog-fruit-vegetable-ipm.extension.umn.edu/2023/01/forcing-chicories-opportunity-for.html; North Carolina State University Extension. (n.d.). Cichorium intybus. NCSU Plant Toolbox. https://plants.ces.ncsu.edu/plants/cichorium-intybus/

Chives

Allium schoenoprasum Amaryllidaceae · very-hardy

Planting windows for Chives
Plant / divide (dormant)	Nov 19 – Mar 2	Plant or divide Nov 19 to Mar 2, while it's dormant. In a county this mild the timing is set by dormancy and nursery shipping, not by frost. Why this date? Air temp below 55F. The dormancy window. Calendar-anchored, NOT frost-relative (fixes v2 root cause 4).

Check it yourself: sow once soil at 2 in reads 35°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing chives in home gardens. https://extension.umn.edu/vegetables/growing-chives; University of Wisconsin-Madison Horticulture Extension. (n.d.). Chives, Allium schoenoprasum. https://hort.extension.wisc.edu/articles/chives-allium-schoenoprasum/

Cilantro / Coriander

Coriandrum sativum Apiaceae · half-hardy

Planting windows for Cilantro / Coriander
Spring sow	Jan 15 – May 4	Sow Jan 15 to May 4. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 40F (Oregon State University Extension minimum for parsley). Latest date is where the crop's heat-and-light budget (62d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 62-day subtraction would give.
Fall sow	Aug 5 – Sep 4	Sow Aug 5 to Sep 4. Later than that and it can't reach size before the light goes in late November. Why this date? Latest date is where the crop's heat-and-light budget still finishes (62d nominal, 1.26x here) before daylength drops under 10h on Nov 23. Half-hardy, so it must arrive nearly finished. The window opens as the late-August heat peak passes; in Santa Clara County you sow into heat, not out of it.

Check it yourself: sow once soil at 2 in reads 40°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Wisconsin-Madison Horticulture Extension. (n.d.). Cilantro / Coriander. https://hort.extension.wisc.edu/articles/cilantro-coriander-coriandrum-sativum/; Oregon State University Extension. (n.d.). How to grow cilantro for leaves or coriander seeds. https://extension.oregonstate.edu/news/how-grow-cilantro-leaves-or-coriander-seeds

Collards

Brassica oleracea var. acephala Brassicaceae · very-hardy

Planting windows for Collards
Spring sow	Jan 15 – Apr 23	Sow Jan 15 to Apr 23. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 40F (Oregon State University Extension minimum for cabbage). Latest date is where the crop's heat-and-light budget (70d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 70-day subtraction would give.
Set out fall transplants	Jul 29 – Sep 3	Set transplants out Jul 29 to Sep 3. It'll hold through the short days and finish as light returns in late January. Why this date? Latest date is where the crop's heat-and-light budget still finishes (70d nominal, 1.91x here) before growth resumes Jan 22. Very-hardy enough to hold through the 10-hour days.
Sow for those transplants	Jun 17 – Jul 30	Raising your own? Sow Jun 17 to Jul 30, about five weeks before they go out. Buying starts is a perfectly good call here. Why this date? Five to six weeks before setting out. Or buy starts, which is what most growers do for the fall brassicas.

Check it yourself: sow once soil at 2 in reads 40°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing collards and kale. https://extension.umn.edu/vegetables/growing-collards-and-kale; Cornell Cooperative Extension. (n.d.). Collards. http://www.gardening.cornell.edu/homegardening/scene6f80.html

Common Thyme (English Thyme)

Thymus vulgaris Lamiaceae · hardy

Planting windows for Common Thyme (English Thyme)
Plant / divide (dormant)	Nov 19 – Mar 2	Plant or divide Nov 19 to Mar 2, while it's dormant. In a county this mild the timing is set by dormancy and nursery shipping, not by frost. Why this date? Air temp below 55F. The dormancy window. Calendar-anchored, NOT frost-relative (fixes v2 root cause 4).

Check it yourself: sow once soil at 2 in reads 65°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

Cornell Cooperative Extension. (n.d.). Thyme growing guide. https://www.gardening.cornell.edu/homegardening/scenede2.html; University of Minnesota Extension. (n.d.). Growing herbs. https://extension.umn.edu/vegetables/growing-herbs

Cucumber (slicing)

Cucumis sativus Cucurbitaceae · tender

Planting windows for Cucumber (slicing)
Start indoors	Mar 15 – Mar 22	Start seed indoors Mar 15 to Mar 22. Why this date? 3-4 weeks before the transplant-out date.
Direct sow	Apr 12 – Jul 24	Sow Apr 12 to Jul 24. Past that there isn't enough warm weather left to fill out a crop. Why this date? Measured soil temperature reaches 60F (practical stand floor; absolute minimum 60F per Oregon State University Extension minimum for cucumber) and nights hold above 48F. Latest date leaves 60d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 60°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing cucumbers. https://extension.umn.edu/vegetables/growing-cucumbers; Oregon State University Extension Service. (n.d.). Grow your own cucumbers. https://extension.oregonstate.edu/gardening/vegetables/grow-your-own-cucumbers

Edamame

Glycine max Fabaceae · tender

Planting windows for Edamame
Direct sow	Apr 12 – Jul 4	Sow Apr 12 to Jul 4. Past that there isn't enough warm weather left to fill out a crop. Why this date? Measured soil temperature reaches 60F (practical stand floor; absolute minimum 60F per Oregon State University Extension minimum for bean) and nights hold above 48F. Latest date leaves 80d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 60°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

South Dakota State University Extension. (n.d.). Edamame: Harvest and storage. https://extension.sdstate.edu/edamame-harvest-and-storage; Oregon State University Extension. (n.d.). Edamame [PNW 525]. https://catalog.extension.oregonstate.edu/pnw525/html; North Carolina State University Extension. (n.d.). Glycine max (edamame, soybean). NCSU Plant Toolbox. https://plants.ces.ncsu.edu/plants/glycine-max/

Eggplant

Solanum melongena Solanaceae · tender

Planting windows for Eggplant
Start indoors	Feb 1 – Feb 15	Start seed indoors Feb 1 to Feb 15. Why this date? 8-10 weeks before the transplant-out date.
Transplant out	Apr 12 – Jul 22	Set plants out Apr 12 to Jul 22, once nights hold above 48°F. Later than that and the warm weather runs out before the fruit does. Why this date? Measured soil temperature reaches 60F (practical stand floor; absolute minimum 60F per Oregon State University Extension minimum for eggplant) and nights hold above 48F. Latest date leaves 62d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 60°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing eggplant in home gardens. https://extension.umn.edu/vegetables/growing-eggplant

Endive (curly / frisée or escarole)

Cichorium endivia Asteraceae · half-hardy

Planting windows for Endive (curly / frisée or escarole)
Spring sow	Jan 15 – Mar 5	Sow Jan 15 to Mar 5. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 35F (Oregon State University Extension minimum for lettuce). Latest date is where the crop's heat-and-light budget (90d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 90-day subtraction would give.
Set out fall transplants	Jul 29 – Aug 5	Set transplants out Jul 29 to Aug 5. Later than that and it won't size up before the light goes in late November. Why this date? Latest date is where the crop's heat-and-light budget still finishes (90d nominal, 1.17x here) before daylength drops under 10h on Nov 23.
Sow for those transplants	Jun 17 – Jul 1	Raising your own? Sow Jun 17 to Jul 1, about five weeks before they go out. Buying starts is a perfectly good call here. Why this date? Five to six weeks before setting out. Or buy starts, which is what most growers do for the fall brassicas.

Check it yourself: sow once soil at 2 in reads 35°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing lettuce, endive and radicchio in home gardens. https://extension.umn.edu/vegetables/growing-lettuce-endive-and-radicchio; Cornell Garden-Based Learning. (n.d.). Vegetable growing guides. https://gardening.cals.cornell.edu/garden-guidance/foodgarden/vegetable-growing-guides/

English Lavender

Lavandula angustifolia Lamiaceae · hardy

Planting windows for English Lavender
Plant / divide (dormant)	Nov 19 – Mar 2	Plant or divide Nov 19 to Mar 2, while it's dormant. In a county this mild the timing is set by dormancy and nursery shipping, not by frost. Why this date? Air temp below 55F. The dormancy window. Calendar-anchored, NOT frost-relative (fixes v2 root cause 4).

Check it yourself: sow once soil at 2 in reads 65°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

Oregon State University Extension Service. (2024). Growing lavender [PDF]. https://extension.oregonstate.edu/sites/extd8/files/documents/bennettl/growing-lavender-2024-1.pdf; Penn State Extension. (n.d.). Adding lavender to your farm. https://extension.psu.edu/adding-lavender-to-your-farm; Utah State University Extension. (n.d.). English lavender in the garden. https://extension.usu.edu/yardandgarden/research/english-lavender-in-the-garden

Epazote

Dysphania ambrosioides Chenopodiaceae · tender

Planting windows for Epazote
Start indoors	Mar 24 – Apr 7	Start seed indoors Mar 24 to Apr 7. Why this date? 4-6 weeks before the transplant-out date.
Direct sow	May 5 – Jul 19	Sow May 5 to Jul 19. Past that there isn't enough warm weather left to fill out a crop. Why this date? Measured soil temperature reaches 65F (practical stand floor; absolute minimum 65F per dataset germination range (low end)) and nights hold above 48F. Latest date leaves 65d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 65°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

Cornell Cooperative Extension. (n.d.). Epazote growing guide. https://www.gardening.cornell.edu/homegardening/; Purdue University Center for New Crops. (n.d.). Chenopodium ambrosioides. https://hort.purdue.edu/newcrop/; University of Florida IFAS Extension. (n.d.). Epazote — Dysphania ambrosioides.

Fennel (Florence / bulb)

Foeniculum vulgare var. azoricum Apiaceae · half-hardy

Planting windows for Fennel (Florence / bulb)
Spring sow	Jan 15 – Apr 9	Sow Jan 15 to Apr 9. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 40F (Oregon State University Extension minimum for parsley). Latest date is where the crop's heat-and-light budget (77d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 77-day subtraction would give.
Fall sow	Aug 5 – Aug 19	Sow Aug 5 to Aug 19. Later than that and it can't reach size before the light goes in late November. Why this date? Latest date is where the crop's heat-and-light budget still finishes (77d nominal, 1.19x here) before daylength drops under 10h on Nov 23. Half-hardy, so it must arrive nearly finished. The window opens as the late-August heat peak passes; in Santa Clara County you sow into heat, not out of it.

Check it yourself: sow once soil at 2 in reads 40°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Wisconsin-Madison Horticulture Extension. (n.d.). Fennel. https://hort.extension.wisc.edu/articles/fennel-foeniculum-vulgare/; Utah State University Extension. (n.d.). Fennel in the garden. https://extension.usu.edu/yardandgarden/research/fennel-in-the-garden

Garden Sage

Salvia officinalis Lamiaceae · very-hardy

Planting windows for Garden Sage
Plant / divide (dormant)	Nov 19 – Mar 2	Plant or divide Nov 19 to Mar 2, while it's dormant. In a county this mild the timing is set by dormancy and nursery shipping, not by frost. Why this date? Air temp below 55F. The dormancy window. Calendar-anchored, NOT frost-relative (fixes v2 root cause 4).

Check it yourself: sow once soil at 2 in reads 60°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

Cornell Cooperative Extension. (n.d.). Sage growing guide. https://www.gardening.cornell.edu/homegardening/sceneeb46.html; University of Minnesota Extension. (n.d.). Growing herbs. https://extension.umn.edu/vegetables/growing-herbs; University of Wisconsin-Madison Horticulture Extension. (n.d.). Sage, Salvia officinalis. https://hort.extension.wisc.edu/articles/sage-salvia-officinalis/

Garlic

Allium sativum Amaryllidaceae · very-hardy

Planting windows for Garlic
Plant cloves	Nov 1 – Nov 30	Plant cloves through November, so they root through the cool months without being tricked into sprouting by autumn warmth. Why this date? November planting, confirmed against Santa Clara County field practice. Cloves root through the cool, wet months without sprouting into autumn warmth.
Lift	Jun 7 – Jun 21	Lift in mid-June. Bulbing is triggered by lengthening days rather than by how long the cloves have been in, so an early and a late November planting finish within the same fortnight. Why this date? Mid-June, anchored to the calendar rather than to days-from-planting. Bulbing is triggered by lengthening days and warming soil, so an early-November and a late-November planting finish within the same fortnight. Replaces both the v2 hardcode and this calendar's own earlier plant-date-plus-N-days rule, which had the wrong shape.

Watch the plant, not the date: lift when the lower third of the leaves have browned and the tops start to lean.

Sources

University of Minnesota Extension. (n.d.). Growing garlic in home gardens. https://extension.umn.edu/vegetables/growing-garlic; Oregon State University Extension. (n.d.). Fall is the best time to plant garlic in Oregon. https://extension.oregonstate.edu/news/get-your-garlic-primer-planting-growing-harvesting-0; Cornell Cooperative Extension. (n.d.). White rot: a returning problem for garlic in New York. https://rvpadmin.cce.cornell.edu/uploads/doc_480.pdf

Ginger

Zingiber officinale Zingiberaceae · tender

Planting windows for Ginger
Plant / divide (dormant)	Nov 19 – Mar 2	Plant or divide Nov 19 to Mar 2, while it's dormant. In a county this mild the timing is set by dormancy and nursery shipping, not by frost. Why this date? Air temp below 55F. The dormancy window. Calendar-anchored, NOT frost-relative (fixes v2 root cause 4).

Check it yourself: sow once soil at 2 in reads 70°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Hawaii at Manoa CTAHR. (n.d.). Hawaiian ginger root production. https://www.ctahr.hawaii.edu/oc/freepubs/pdf/CFS-Ginger.pdf; University of Florida IFAS Extension. (n.d.). Ginger production in Florida. https://edis.ifas.ufl.edu/publication/HS1185; North Carolina State University Extension. (n.d.). Zingiber officinale. NCSU Plant Toolbox. https://plants.ces.ncsu.edu/plants/zingiber-officinale/

Globe Artichoke

Cynara scolymus Asteraceae · half-hardy

Planting windows for Globe Artichoke
Plant / divide (dormant)	Nov 19 – Mar 2	Plant or divide Nov 19 to Mar 2, while it's dormant. In a county this mild the timing is set by dormancy and nursery shipping, not by frost. Why this date? Air temp below 55F. The dormancy window. Calendar-anchored, NOT frost-relative (fixes v2 root cause 4).

Check it yourself: sow once soil at 2 in reads 35°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

Cornell Garden-Based Learning. (n.d.). Globe artichokes growing guide. https://gardening.cals.cornell.edu/garden-guidance/foodgarden/vegetable-growing-guides/globe-artichokes-growing-guide/; Cornell University. (n.d.). Explore Cornell — Home gardening: Artichoke growing guide. http://www.gardening.cornell.edu/homegardening/scenec09b.html; Utah State University Extension. (n.d.). Artichokes. https://extension.usu.edu/yardandgarden/vegetables/artichokes; Drost, D. (n.d.). How to grow artichoke in your garden. Utah State University Extension. https://extension.usu.edu/yardandgarden/research/artichoke-in-the-garden; North Carolina State University Extension. (n.d.). Cynara cardunculus Scolymus Group. NCSU Plant Toolbox. https://plants.ces.ncsu.edu/plants/cynara-cardunculus-scolymus-group/

Greek Oregano

Origanum vulgare subsp. hirtum Lamiaceae · hardy

Planting windows for Greek Oregano
Plant / divide (dormant)	Nov 19 – Mar 2	Plant or divide Nov 19 to Mar 2, while it's dormant. In a county this mild the timing is set by dormancy and nursery shipping, not by frost. Why this date? Air temp below 55F. The dormancy window. Calendar-anchored, NOT frost-relative (fixes v2 root cause 4).

Check it yourself: sow once soil at 2 in reads 65°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

Cornell Cooperative Extension. (n.d.). Oregano growing guide. https://www.gardening.cornell.edu/homegardening/scene2a91.html; University of Minnesota Extension. (n.d.). Growing herbs. https://extension.umn.edu/vegetables/growing-herbs; Penn State Extension. (n.d.). Herbs for the home gardener. https://extension.psu.edu/herbs-for-the-home-gardener

Green Onion / Scallion

Allium fistulosum Amaryllidaceae · very-hardy

Planting windows for Green Onion / Scallion
Spring sow	Jan 15 – Apr 23	Sow Jan 15 to Apr 23. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 35F (Oregon State University Extension minimum for onion). Latest date is where the crop's heat-and-light budget (70d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 70-day subtraction would give.
Fall sow	Aug 5 – Sep 3	Sow Aug 5 to Sep 3. It's hardy enough to sit out the short days and finish as light returns in late January. Why this date? Latest date is where the crop's heat-and-light budget still finishes (70d nominal, 1.91x here) before growth resumes Jan 22. Very-hardy enough to hold in the field through the 10-hour days and finish as light returns. The window opens as the late-August heat peak passes; in Santa Clara County you sow into heat, not out of it.

Check it yourself: sow once soil at 2 in reads 35°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing scallions in home gardens. https://extension.umn.edu/vegetables/growing-scallions-home-gardens

Ground Cherry (Aunt Molly's)

Physalis pruinosa Solanaceae · tender

Planting windows for Ground Cherry (Aunt Molly's)
Start indoors	Feb 15 – Feb 22	Start seed indoors Feb 15 to Feb 22. Why this date? 7-8 weeks before the transplant-out date.
Transplant out	Apr 12 – Jul 14	Set plants out Apr 12 to Jul 14, once nights hold above 48°F. Later than that and the warm weather runs out before the fruit does. Why this date? Measured soil temperature reaches 60F (practical stand floor; absolute minimum 50F per Oregon State University Extension minimum for tomato) and nights hold above 48F. Latest date leaves 70d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 60°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing tomatillos and ground cherries. https://extension.umn.edu/vegetables/growing-tomatillos-and-ground-cherries; Seed Savers Exchange. (n.d.). Growing guide: Ground cherry. https://seedsavers.org/grow-ground-cherry/

Head Lettuce (butterhead)

Lactuca sativa Asteraceae · half-hardy

Planting windows for Head Lettuce (butterhead)
Spring sow	Jan 15 – Apr 30	Sow Jan 15 to Apr 30. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 35F (Oregon State University Extension minimum for lettuce). Latest date is where the crop's heat-and-light budget (65d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 65-day subtraction would give.
Set out fall transplants	Jul 29 – Sep 1	Set transplants out Jul 29 to Sep 1. Later than that and it won't size up before the light goes in late November. Why this date? Latest date is where the crop's heat-and-light budget still finishes (65d nominal, 1.25x here) before daylength drops under 10h on Nov 23.
Sow for those transplants	Jun 17 – Jul 28	Raising your own? Sow Jun 17 to Jul 28, about five weeks before they go out. Buying starts is a perfectly good call here. Why this date? Five to six weeks before setting out. Or buy starts, which is what most growers do for the fall brassicas.

Check it yourself: sow once soil at 2 in reads 35°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing lettuce, endive and radicchio in home gardens. https://extension.umn.edu/vegetables/growing-lettuce-endive-and-radicchio; University of Minnesota Extension Fruit & Vegetable IPM. (2026). Gearing up to grow: Head lettuce. https://blog-fruit-vegetable-ipm.extension.umn.edu/2026/04/gearing-up-to-grow-head-lettuce.html; Cornell Garden-Based Learning. (n.d.). Vegetable growing guides. https://gardening.cals.cornell.edu/garden-guidance/foodgarden/vegetable-growing-guides/

Jicama / Mexican Yam Bean

Pachyrhizus erosus Fabaceae · tender

Planting windows for Jicama / Mexican Yam Bean
Start indoors	Apr 10 – Apr 24	Start seed indoors Apr 10 to Apr 24. Why this date? 6-8 weeks before the transplant-out date.
Direct sow	Jun 5 – Jun 19	Sow Jun 5 to Jun 19. Past that there isn't enough warm weather left to fill out a crop. Why this date? Measured soil temperature reaches 70F (practical stand floor; absolute minimum 70F per dataset germination range (low end)) and nights hold above 48F. Latest date leaves 225d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 70°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

This one only just fits our summer. Pick the fastest-maturing variety you can find.

Sources

University of Florida IFAS Extension. (n.d.). Jicama — a new fruit and vegetable. https://edis.ifas.ufl.edu/publication/HS940; University of Hawaii at Manoa CTAHR. (n.d.). Yam bean (jicama) production. https://www.ctahr.hawaii.edu/oc/freepubs/; Purdue University Center for New Crops. (n.d.). Pachyrhizus erosus. https://hort.purdue.edu/newcrop/CropFactSheets/jicama.html

Kabocha (Japanese winter squash)

Cucurbita maxima Cucurbitaceae · tender

Planting windows for Kabocha (Japanese winter squash)
Start indoors	Mar 15 – Mar 29	Start seed indoors Mar 15 to Mar 29. Why this date? 2-4 weeks before the transplant-out date.
Direct sow	Apr 12 – Jun 22	Sow Apr 12 to Jun 22. Past that there isn't enough warm weather left to fill out a crop. Why this date? Measured soil temperature reaches 60F (practical stand floor; absolute minimum 60F per Oregon State University Extension minimum for squash) and nights hold above 48F. Latest date leaves 92d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 60°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

Leek

Allium ampeloprasum Amaryllidaceae · very-hardy

Planting windows for Leek
Spring sow	Jan 15 – Feb 21	Sow Jan 15 to Feb 21. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 35F (Oregon State University Extension minimum for onion). Latest date is where the crop's heat-and-light budget (120d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 120-day subtraction would give.
Set out transplants (main season)	Jun 12 – Jul 12	Set transplants out Jun 12 to Jul 12, for a crop that finishes into the cool months. Why this date? Latest date is where the crop's heat-and-light budget still finishes (120d nominal, 1.55x here) before growth resumes Jan 22. Very-hardy enough to hold through the 10-hour days.
Sow for those transplants	May 1 – Jun 7	Raising your own? Sow May 1 to Jun 7, about five weeks before they go out. Buying starts is a perfectly good call here. Why this date? Five to six weeks before setting out. Or buy starts, which is what most growers do for the fall brassicas.

Check it yourself: sow once soil at 2 in reads 35°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing leeks in home gardens. https://extension.umn.edu/vegetables/growing-leeks; Utah State University Extension. (n.d.). How to grow leeks in your garden. https://extension.usu.edu/yardandgarden/research/leeks-in-the-garden; University of Maryland Extension. (n.d.). Growing leeks in a home garden. https://extension.umd.edu/resource/growing-leeks-home-garden

Lemongrass

Cymbopogon citratus Poaceae · tender

Planting windows for Lemongrass
Plant / divide (dormant)	Nov 19 – Mar 2	Plant or divide Nov 19 to Mar 2, while it's dormant. In a county this mild the timing is set by dormancy and nursery shipping, not by frost. Why this date? Air temp below 55F. The dormancy window. Calendar-anchored, NOT frost-relative (fixes v2 root cause 4).

Check it yourself: sow once soil at 2 in reads 70°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

Penn State Extension. (n.d.). Lemongrass. https://extension.psu.edu/lemongrass; North Carolina State University Extension. (n.d.). Cymbopogon citratus. NCSU Plant Toolbox. https://plants.ces.ncsu.edu/plants/cymbopogon-citratus/; Oregon State University Extension Service. (n.d.). Growing lemongrass at home. https://extension.oregonstate.edu/gardening/techniques/growing-lemongrass-home; University of Minnesota Extension. (n.d.). Yard and Garden News — Growing lemongrass in Minnesota. https://blog-yard-garden-news.extension.umn.edu/; Maia, M. F., & Moore, S. J. (2011). Plant-based insect repellents: a review of their efficacy, development and testing. Malaria Journal, 10(Suppl 1), S11. https://malariajournal.biomedcentral.com/articles/10.1186/1475-2875-10-S1-S11

Malabar Spinach

Basella alba Basellaceae · tender

Planting windows for Malabar Spinach
Start indoors	Apr 10 – Apr 24	Start seed indoors Apr 10 to Apr 24. Why this date? 6-8 weeks before the transplant-out date.
Direct sow	Jun 5 – Jul 7	Sow Jun 5 to Jul 7. Past that there isn't enough warm weather left to fill out a crop. Why this date? Measured soil temperature reaches 70F (practical stand floor; absolute minimum 70F per dataset germination range (low end)) and nights hold above 48F. Latest date leaves 77d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 70°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Florida IFAS Extension. (n.d.). Malabar spinach. https://edis.ifas.ufl.edu/publication/MV132; University of Hawaii at Manoa CTAHR. (n.d.). Malabar spinach production. https://www.ctahr.hawaii.edu/oc/freepubs/; North Carolina State University Extension. (n.d.). Basella alba. NCSU Plant Toolbox. https://plants.ces.ncsu.edu/plants/basella-alba/

Nopales / Paddle Cactus

Opuntia ficus-indica Cactaceae · semi-hardy

Planting windows for Nopales / Paddle Cactus
Plant / divide (dormant)	Nov 19 – Mar 2	Plant or divide Nov 19 to Mar 2, while it's dormant. In a county this mild the timing is set by dormancy and nursery shipping, not by frost. Why this date? Air temp below 55F. The dormancy window. Calendar-anchored, NOT frost-relative (fixes v2 root cause 4).

Sources

University of Arizona Cooperative Extension. (n.d.). Prickly pear cactus. https://extension.arizona.edu/; New Mexico State University Cooperative Extension. (n.d.). Prickly pear cactus production. https://pubs.nmsu.edu/

Okra

Abelmoschus esculentus Malvaceae · tender

Planting windows for Okra
Start indoors	May 29 – Jun 12	Start seed indoors May 29 to Jun 12. Why this date? 4-6 weeks before the transplant-out date.
Direct sow	Jul 10 – Jul 24	Sow Jul 10 to Jul 24. Past that there isn't enough warm weather left to fill out a crop. Why this date? Measured soil temperature reaches 75F (practical stand floor; absolute minimum 75F per dataset germination range (low end)) and nights hold above 48F. Latest date leaves 60d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 75°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

Clemson Cooperative Extension. (n.d.). Okra. https://hgic.clemson.edu/factsheet/okra/; University of Florida IFAS Extension. (n.d.). Okra in Florida. https://edis.ifas.ufl.edu/publication/MV120; North Carolina State University Extension. (n.d.). Abelmoschus esculentus. NCSU Plant Toolbox. https://plants.ces.ncsu.edu/plants/abelmoschus-esculentus/

Parsley

Petroselinum crispum Apiaceae · hardy

Planting windows for Parsley
Spring sow	Jan 15 – Apr 3	Sow Jan 15 to Apr 3. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 40F (Oregon State University Extension minimum for parsley). Latest date is where the crop's heat-and-light budget (80d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 80-day subtraction would give.
Fall sow	Aug 5 – Aug 23	Sow Aug 5 to Aug 23. It's hardy enough to sit out the short days and finish as light returns in late January. Why this date? Latest date is where the crop's heat-and-light budget still finishes (80d nominal, 1.81x here) before growth resumes Jan 22. Hardy enough to hold in the field through the 10-hour days and finish as light returns. The window opens as the late-August heat peak passes; in Santa Clara County you sow into heat, not out of it.

Check it yourself: sow once soil at 2 in reads 40°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing parsley. https://extension.umn.edu/vegetables/growing-parsley; University of Wisconsin-Madison Horticulture Extension. (n.d.). Parsley. https://hort.extension.wisc.edu/articles/parsley-petroselinum-crispum/; North Carolina State University Extension. (n.d.). Parsleyworm. https://content.ces.ncsu.edu/parsleyworm

Parsnip

Pastinaca sativa Apiaceae · very-hardy

Planting windows for Parsnip
Spring sow	Jan 15 – Mar 3	Sow Jan 15 to Mar 3. Push past that and the heat arriving in late June catches it before it's ready. Why this date? Measured soil temperature reaches 35F (Oregon State University Extension minimum for parsnip). Latest date is where the crop's heat-and-light budget (110d of growth) still finishes before sustained heat begins Jun 21. Cold winter sowings spend that budget slowly, so this is later than a plain 110-day subtraction would give.

Check it yourself: sow once soil at 2 in reads 35°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Too slow to finish before the short days arrive. Sow it in spring instead, or carry it through winter under cover.

Sources

University of Minnesota Extension. (n.d.). Growing carrots and parsnips. https://extension.umn.edu/vegetables/growing-carrots-and-parsnips; Utah State University Extension. (n.d.). Wild parsnip identification and control. https://extension.usu.edu/yardandgarden/research/wild-parsnip-pastinaca-sativa-identification-and-control-in-residential-landscapes

Peppermint

Mentha × piperita Lamiaceae · very-hardy

Planting windows for Peppermint
Plant / divide (dormant)	Nov 19 – Mar 2	Plant or divide Nov 19 to Mar 2, while it's dormant. In a county this mild the timing is set by dormancy and nursery shipping, not by frost. Why this date? Air temp below 55F. The dormancy window. Calendar-anchored, NOT frost-relative (fixes v2 root cause 4).

Sources

Cornell Cooperative Extension. (n.d.). Mint growing guide. https://www.gardening.cornell.edu/homegardening/scenef93f.html; Oregon State University Extension Service. (n.d.). Growing mint in the home garden. https://extension.oregonstate.edu/gardening/techniques/growing-mint-home-garden

Perilla / Shiso

Perilla frutescens Lamiaceae · tender

Planting windows for Perilla / Shiso
Start indoors	Mar 10 – Mar 24	Start seed indoors Mar 10 to Mar 24. Why this date? 6-8 weeks before the transplant-out date.
Direct sow	May 5 – Jul 4	Sow May 5 to Jul 4. Past that there isn't enough warm weather left to fill out a crop. Why this date? Measured soil temperature reaches 65F (practical stand floor; absolute minimum 65F per dataset germination range (low end)) and nights hold above 48F. Latest date leaves 80d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 65°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

North Carolina State University Extension. (n.d.). Perilla frutescens. NCSU Plant Toolbox. https://plants.ces.ncsu.edu/plants/perilla-frutescens/; University of Hawaii at Manoa CTAHR. (n.d.). Shiso production. https://www.ctahr.hawaii.edu/oc/freepubs/; Tennessee Invasive Plant Council. (n.d.). Perilla frutescens. https://www.tnipc.org/

Pole Bean

Phaseolus vulgaris Fabaceae · tender

Planting windows for Pole Bean
Direct sow	Apr 12 – Jul 22	Sow Apr 12 to Jul 22. Past that there isn't enough warm weather left to fill out a crop. Why this date? Measured soil temperature reaches 60F (practical stand floor; absolute minimum 60F per Oregon State University Extension minimum for bean) and nights hold above 48F. Latest date leaves 62d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 60°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

Pumpkin (carving)

Cucurbita pepo Cucurbitaceae · tender

Planting windows for Pumpkin (carving)
Start indoors	Mar 15 – Mar 29	Start seed indoors Mar 15 to Mar 29. Why this date? 2-4 weeks before the transplant-out date.
Direct sow	Apr 12 – Jun 7	Sow Apr 12 to Jun 7. Past that there isn't enough warm weather left to fill out a crop. Why this date? Measured soil temperature reaches 60F (practical stand floor; absolute minimum 60F per Oregon State University Extension minimum for pumpkin) and nights hold above 48F. Latest date leaves 107d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 60°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing winter squash and pumpkins. https://extension.umn.edu/vegetables/pumpkins-and-winter-squash; Penn State Extension. (n.d.). Pumpkin production. https://extension.psu.edu/pumpkin-production

Roselle / Jamaica / Sorrel

Hibiscus sabdariffa Malvaceae · tender

Planting windows for Roselle / Jamaica / Sorrel
Start indoors	Mar 27 – Apr 24	Start seed indoors Mar 27 to Apr 24. Why this date? 6-10 weeks before the transplant-out date.
Direct sow	Jun 5 – Jun 19	Sow Jun 5 to Jun 19. Past that there isn't enough warm weather left to fill out a crop. Why this date? Measured soil temperature reaches 70F (practical stand floor; absolute minimum 70F per dataset germination range (low end)) and nights hold above 48F. Latest date leaves 180d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 70°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

This one only just fits our summer. Pick the fastest-maturing variety you can find.

Sources

University of Florida IFAS Extension. (n.d.). Roselle — Hibiscus sabdariffa. https://edis.ifas.ufl.edu/publication/HS659; University of Hawaii at Manoa CTAHR. (n.d.). Roselle production guide. https://www.ctahr.hawaii.edu/oc/freepubs/; Purdue University Center for New Crops. (n.d.). Hibiscus sabdariffa. https://hort.purdue.edu/newcrop/CropFactSheets/roselle.html

Rosemary

Salvia rosmarinus Lamiaceae · tender to hardy (cultivar-dependent)

Planting windows for Rosemary
Plant / divide (dormant)	Nov 19 – Mar 2	Plant or divide Nov 19 to Mar 2, while it's dormant. In a county this mild the timing is set by dormancy and nursery shipping, not by frost. Why this date? Air temp below 55F. The dormancy window. Calendar-anchored, NOT frost-relative (fixes v2 root cause 4).

Check it yourself: sow once soil at 2 in reads 65°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

North Carolina State University Extension. (n.d.). Salvia rosmarinus. NCSU Plant Toolbox. https://plants.ces.ncsu.edu/plants/salvia-rosmarinus/; Oregon State University Extension Service. (n.d.). Five cold-hardy herbs to grow at home. https://extension.oregonstate.edu/gardening/vegetables/five-cold-hardy-herbs-grow-home; Penn State Extension. (n.d.). Herb garden plants: Rosemary. https://extension.psu.edu/herb-garden-plants-rosemary

Shallot

Allium cepa var. aggregatum Amaryllidaceae · hardy

Planting windows for Shallot
Plant cloves	Nov 1 – Nov 30	Plant cloves through November, so they root through the cool months without being tricked into sprouting by autumn warmth. Why this date? November planting, confirmed against Santa Clara County field practice. Cloves root through the cool, wet months without sprouting into autumn warmth.
Lift	Jun 7 – Jun 21	Lift in mid-June. Bulbing is triggered by lengthening days rather than by how long the cloves have been in, so an early and a late November planting finish within the same fortnight. Why this date? Mid-June, anchored to the calendar rather than to days-from-planting. Bulbing is triggered by lengthening days and warming soil, so an early-November and a late-November planting finish within the same fortnight. Replaces both the v2 hardcode and this calendar's own earlier plant-date-plus-N-days rule, which had the wrong shape.

Check it yourself: sow once soil at 2 in reads 35°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Watch the plant, not the date: lift when the lower third of the leaves have browned and the tops start to lean.

Sources

Oregon State University College of Agricultural Sciences. (n.d.). Shallots — Oregon vegetables. https://horticulture.oregonstate.edu/oregon-vegetables/shallots-0; University of Minnesota Extension. (n.d.). Growing onions in home gardens. https://extension.umn.edu/vegetables/growing-onions

Strawberry (June-bearing)

Fragaria × ananassa Rosaceae · hardy

Planting windows for Strawberry (June-bearing)
Plant / divide (dormant)	Nov 19 – Mar 2	Plant or divide Nov 19 to Mar 2, while it's dormant. In a county this mild the timing is set by dormancy and nursery shipping, not by frost. Why this date? Air temp below 55F. The dormancy window. Calendar-anchored, NOT frost-relative (fixes v2 root cause 4).

Bare-root crowns ship November to February, and here they go in during that dormant window rather than in spring.

Sources

Cornell Cooperative Extension. (n.d.). Strawberry production guide. https://www.gardening.cornell.edu/homegardening/scenec00f.html; Oregon State University Extension Service. (n.d.). Growing strawberries in your home garden. https://extension.oregonstate.edu/gardening/fruit/growing-strawberries-your-home-garden; Penn State Extension. (n.d.). Strawberries in home fruit plantings. https://extension.psu.edu/strawberries-in-home-fruit-plantings

Summer Squash (yellow / pattypan)

Cucurbita pepo Cucurbitaceae · tender

Planting windows for Summer Squash (yellow / pattypan)
Start indoors	Mar 15 – Mar 29	Start seed indoors Mar 15 to Mar 29. Why this date? 2-4 weeks before the transplant-out date.
Direct sow	Apr 12 – Aug 1	Sow Apr 12 to Aug 1. Past that there isn't enough warm weather left to fill out a crop. Why this date? Measured soil temperature reaches 60F (practical stand floor; absolute minimum 60F per Oregon State University Extension minimum for squash) and nights hold above 48F. Latest date leaves 52d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 60°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing summer squash and zucchini. https://extension.umn.edu/vegetables/growing-summer-squash-and-zucchini

Sunflower (seed-type, Mammoth Russian)

Helianthus annuus Asteraceae · tender

Planting windows for Sunflower (seed-type, Mammoth Russian)
Direct sow	Jun 5 – Jun 14	Sow Jun 5 to Jun 14. Past that there isn't enough warm weather left to fill out a crop. Why this date? Measured soil temperature reaches 70F (practical stand floor; absolute minimum 70F per dataset germination range (low end)) and nights hold above 48F. Latest date leaves 100d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 70°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

Oregon State University Extension Service. (n.d.). Grow your own sunflowers (EM 9866). https://extension.oregonstate.edu/catalog/em-9866-grow-your-own-sunflowers; University of Minnesota Extension. (n.d.). Sunflowers. https://extension.umn.edu/flowers/sunflowers; Penn State Extension. (n.d.). Sunflowers (Helianthus annuus): Planting and growing a home garden. https://extension.psu.edu/sunflowers-helianthus-annuus; Penn State Extension. (n.d.). Allelopathy in the home garden. https://extension.psu.edu/allelopathy-in-the-home-garden; Bogatek, R., Gniazdowska, A., Zakrzewska, W., Oracz, K., & Gawronski, S. W. (2006). Allelopathic effects of sunflower extracts on mustard seed germination and seedling growth. Biologia Plantarum, 50(1), 156-158. https://pubmed.ncbi.nlm.nih.gov/17131190/; Macias, F. A., et al. (2023). The allelopathic activity of aqueous extracts of Helianthus annuus L. on Pisum sativum L. PMC. https://pmc.ncbi.nlm.nih.gov/articles/PMC10180669/

Sweet Basil (Genovese-type)

Ocimum basilicum Lamiaceae · tender

Planting windows for Sweet Basil (Genovese-type)
Start indoors	Feb 15 – Mar 1	Start seed indoors Feb 15 to Mar 1. Why this date? 6-8 weeks before the transplant-out date.
Direct sow	Apr 12 – Jul 19	Sow Apr 12 to Jul 19. Past that there isn't enough warm weather left to fill out a crop. Why this date? Measured soil temperature reaches 60F (practical stand floor; absolute minimum 60F per dataset germination range (low end)) and nights hold above 48F. Latest date leaves 65d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 60°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing basil in home gardens. https://extension.umn.edu/vegetables/growing-basil

Sweet Corn

Zea mays var. saccharata (also seen as var. rugosa) Poaceae · tender

Planting windows for Sweet Corn
Direct sow	Apr 12 – Jul 4	Sow Apr 12 to Jul 4. Past that there isn't enough warm weather left to fill out a crop. Why this date? Measured soil temperature reaches 60F (practical stand floor; absolute minimum 50F per Oregon State University Extension minimum for corn) and nights hold above 48F. Latest date leaves 80d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 60°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

Cornell Garden-Based Learning. (n.d.). Corn growing guide. Cornell Cooperative Extension. https://gardening.cals.cornell.edu/garden-guidance/foodgarden/vegetable-growing-guides/corn-growing-guide/; University of Minnesota Extension. (n.d.). Growing sweet corn in home gardens. https://extension.umn.edu/vegetables/growing-sweet-corn; Oregon State University Extension Service. (n.d.). Grow your own sweet corn (EC 1379). https://extension.oregonstate.edu/catalog/ec-1379-grow-your-own-sweet-corn; Penn State Extension. (n.d.). Sweet corn in the home garden. https://extension.psu.edu/sweet-corn-in-the-home-garden; North Carolina State University Extension. (n.d.). Sweet corn production. https://content.ces.ncsu.edu/sweet-corn-production; University of Minnesota Extension. (n.d.). Common smut of corn. https://extension.umn.edu/disease-management/common-smut-corn; Penn State Extension. (n.d.). Corn earworm as a pest of sweet corn. https://extension.psu.edu/corn-earworm-as-a-pest-of-sweet-corn

Sweet Marjoram

Origanum majorana Lamiaceae · tender

Planting windows for Sweet Marjoram
Start indoors	Mar 10 – Mar 24	Start seed indoors Mar 10 to Mar 24. Why this date? 6-8 weeks before the transplant-out date.
Direct sow	May 5 – Jul 9	Sow May 5 to Jul 9. Past that there isn't enough warm weather left to fill out a crop. Why this date? Measured soil temperature reaches 65F (practical stand floor; absolute minimum 65F per dataset germination range (low end)) and nights hold above 48F. Latest date leaves 75d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 65°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

Cornell Cooperative Extension. (n.d.). Marjoram growing guide. https://www.gardening.cornell.edu/homegardening/scene75ce.html; University of Minnesota Extension. (n.d.). Growing herbs. https://extension.umn.edu/vegetables/growing-herbs; Penn State Extension. (n.d.). Herbs for the home gardener. https://extension.psu.edu/herbs-for-the-home-gardener

Sweet Pepper (bell-type)

Capsicum annuum Solanaceae · tender

Planting windows for Sweet Pepper (bell-type)
Start indoors	Feb 15 – Mar 1	Start seed indoors Feb 15 to Mar 1. Why this date? 6-8 weeks before the transplant-out date.
Transplant out	Apr 12 – Jul 14	Set plants out Apr 12 to Jul 14, once nights hold above 48°F. Later than that and the warm weather runs out before the fruit does. Why this date? Measured soil temperature reaches 60F (practical stand floor; absolute minimum 60F per Oregon State University Extension minimum for pepper) and nights hold above 48F. Latest date leaves 70d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 60°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing peppers. https://extension.umn.edu/vegetables/growing-peppers

Sweet Potato

Ipomoea batatas Convolvulaceae · tender

Planting windows for Sweet Potato
Transplant out	Apr 12 – Jun 9	Set plants out Apr 12 to Jun 9, once nights hold above 48°F. Later than that and the warm weather runs out before the fruit does. Why this date? Measured soil temperature reaches 60F (practical stand floor; absolute minimum NoneF per None) and nights hold above 48F. Latest date leaves 105d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 60°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

North Carolina State University Extension. (n.d.). Sweetpotatoes. https://content.ces.ncsu.edu/sweetpotatoes; University of Florida IFAS Extension. (n.d.). Sweetpotato in Florida. https://edis.ifas.ufl.edu/publication/HS131; LSU AgCenter. (n.d.). Sweet potato production guide. https://www.lsuagcenter.com/topics/crops/sweet-potatoes

Thai Basil

Ocimum basilicum var. thyrsiflora Lamiaceae · tender

Planting windows for Thai Basil
Start indoors	Apr 24 – May 8	Start seed indoors Apr 24 to May 8. Why this date? 4-6 weeks before the transplant-out date.
Direct sow	Jun 5 – Aug 3	Sow Jun 5 to Aug 3. Past that there isn't enough warm weather left to fill out a crop. Why this date? Measured soil temperature reaches 70F (practical stand floor; absolute minimum 70F per dataset germination range (low end)) and nights hold above 48F. Latest date leaves 50d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 70°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

North Carolina State University Extension. (n.d.). Ocimum basilicum var. thyrsiflora. NCSU Plant Toolbox. https://plants.ces.ncsu.edu/plants/ocimum-basilicum-var-thyrsiflora/; Cornell Cooperative Extension. (n.d.). Basil cultivar trials. https://www.gardening.cornell.edu/homegardening/; University of Hawaii at Manoa CTAHR. (n.d.). Basil production. https://www.ctahr.hawaii.edu/oc/freepubs/

Tomatillo (large green)

Physalis philadelphica Solanaceae · tender

Planting windows for Tomatillo (large green)
Start indoors	Mar 1 – Mar 15	Start seed indoors Mar 1 to Mar 15. Why this date? 4-6 weeks before the transplant-out date.
Transplant out	Apr 12 – Jun 27	Set plants out Apr 12 to Jun 27, once nights hold above 48°F. Later than that and the warm weather runs out before the fruit does. Why this date? Measured soil temperature reaches 60F (practical stand floor; absolute minimum 50F per Oregon State University Extension minimum for tomato) and nights hold above 48F. Latest date leaves 87d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 60°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing tomatillos and ground cherries. https://extension.umn.edu/vegetables/growing-tomatillos-and-ground-cherries

Tomato (indeterminate slicing)

Solanum lycopersicum Solanaceae · tender

Planting windows for Tomato (indeterminate slicing)
Start indoors	Mar 1 – Mar 8	Start seed indoors Mar 1 to Mar 8. Why this date? 5-6 weeks before the transplant-out date.
Transplant out	Apr 12 – Jul 7	Set plants out Apr 12 to Jul 7, once nights hold above 48°F. Later than that and the warm weather runs out before the fruit does. Why this date? Measured soil temperature reaches 60F (practical stand floor; absolute minimum 50F per Oregon State University Extension minimum for tomato) and nights hold above 48F. Latest date leaves 77d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 60°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing tomatoes in home gardens. https://extension.umn.edu/vegetables/growing-tomatoes; Cornell Garden-Based Learning. (n.d.). Tomato growing guide. https://gardening.cals.cornell.edu/garden-guidance/foodgarden/vegetable-growing-guides/tomato-growing-guide/

Turmeric

Curcuma longa Zingiberaceae · tender

Planting windows for Turmeric
Plant / divide (dormant)	Nov 19 – Mar 2	Plant or divide Nov 19 to Mar 2, while it's dormant. In a county this mild the timing is set by dormancy and nursery shipping, not by frost. Why this date? Air temp below 55F. The dormancy window. Calendar-anchored, NOT frost-relative (fixes v2 root cause 4).

Check it yourself: sow once soil at 2 in reads 70°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Hawaii at Manoa CTAHR. (n.d.). Turmeric production in Hawaii. https://www.ctahr.hawaii.edu/oc/freepubs/; University of Florida IFAS Extension. (n.d.). Turmeric — Curcuma longa. https://edis.ifas.ufl.edu/publication/HS1419; North Carolina State University Extension. (n.d.). Curcuma longa. NCSU Plant Toolbox. https://plants.ces.ncsu.edu/plants/curcuma-longa/

Vietnamese Coriander / Rau Ram

Persicaria odorata Polygonaceae · tender

Planting windows for Vietnamese Coriander / Rau Ram
Plant / divide (dormant)	Nov 19 – Mar 2	Plant or divide Nov 19 to Mar 2, while it's dormant. In a county this mild the timing is set by dormancy and nursery shipping, not by frost. Why this date? Air temp below 55F. The dormancy window. Calendar-anchored, NOT frost-relative (fixes v2 root cause 4).

Check it yourself: sow once soil at 2 in reads 60°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Hawaii at Manoa CTAHR. (n.d.). Vietnamese coriander production. https://www.ctahr.hawaii.edu/oc/freepubs/; University of Florida IFAS Extension. (n.d.). Persicaria odorata.; North Carolina State University Extension. (n.d.). Persicaria odorata. NCSU Plant Toolbox. https://plants.ces.ncsu.edu/plants/persicaria-odorata/

Watermelon

Citrullus lanatus Cucurbitaceae · tender

Planting windows for Watermelon
Start indoors	Mar 15 – Mar 22	Start seed indoors Mar 15 to Mar 22. Why this date? 3-4 weeks before the transplant-out date.
Direct sow	Apr 12 – Jul 2	Sow Apr 12 to Jul 2. Past that there isn't enough warm weather left to fill out a crop. Why this date? Measured soil temperature reaches 60F (practical stand floor; absolute minimum 60F per Oregon State University Extension minimum for watermelon) and nights hold above 48F. Latest date leaves 82d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 60°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing watermelon. https://extension.umn.edu/fruit/growing-melons-home-garden; Penn State Extension. (n.d.). Watermelon production. https://extension.psu.edu/watermelon-production

Zucchini

Cucurbita pepo Cucurbitaceae · tender

Planting windows for Zucchini
Start indoors	Mar 15 – Mar 29	Start seed indoors Mar 15 to Mar 29. Why this date? 2-4 weeks before the transplant-out date.
Direct sow	Apr 12 – Aug 3	Sow Apr 12 to Aug 3. Past that there isn't enough warm weather left to fill out a crop. Why this date? Measured soil temperature reaches 60F (practical stand floor; absolute minimum 60F per Oregon State University Extension minimum for squash) and nights hold above 48F. Latest date leaves 50d to maturity before warm weather ends Sep 22. Heat, not the Dec 6 frost, is what bounds this.

Check it yourself: sow once soil at 2 in reads 60°F or more in the morning. These dates are what an average Santa Clara year does. Your bed is the authority.

Sources

University of Minnesota Extension. (n.d.). Growing summer squash and zucchini. https://extension.umn.edu/vegetables/growing-summer-squash-and-zucchini; Penn State Extension. (n.d.). Summer squash production. https://extension.psu.edu/zucchini

How these dates were worked out

The climate spine is NOAA's 1991–2020 daily normals for San Jose International Airport, with frost dates from the Los Gatos cooperative station. Soil temperature and daily light come from the three CIMIS weather stations in this county — San Jose, Morgan Hill and Gilroy — pooled from 13,793 quality-checked station-days of paired air and soil readings and 13,872 daily solar radiation readings.

Crop thresholds come from a dataset of 80 entries built on extension and peer-reviewed sources, chiefly the Universities of Minnesota, Cornell, Penn State, North Carolina State and Oregon State. Days-to-maturity is treated as a heat-and-light budget rather than a countdown, and spent forward from each candidate sowing date, which is why an August sowing can beat its seed-packet figure while an October one of the same crop may not finish at all.

A calendar date is always an average-year estimate. That is why every crop above also gives you the soil temperature to check for. A $6 thermometer in your own bed beats our arithmetic.