Winter Squash in Zone 10a & 10b
Cucurbita maxima
When to plant winter squash in zone 10b
Zones 10a and 10b share the same average frost dates in our data, so this page covers both.
Method: Start indoors: Start indoors from seed, then transplant outside. In your zone, Winter Squash needs a head start on the heat that direct-sowing elsewhere doesn't require.
| Window | Spring window |
|---|---|
| Start indoors | Feb |
| Direct sow / transplant outside | Mar |
| Estimated harvest | Jun 9–Jul 9 (~100 days after transplanting) |
| Window | Monsoon window |
|---|---|
| Start indoors | Jun–Jul |
| Direct sow / transplant outside | Jul–Aug |
| Estimated harvest | Oct 9–Dec 9 (~100 days after transplanting) |
Spacing: about 4 square feet per plant (square-foot-gardening spacing). Mature height: 1-1.5 ft.
Zone 10b dates sourced from growinginthegarden.com.
Winter squash is a long game: direct-seeded after your last frost, it takes around 100 days to mature, the longest of the common squash-family crops, and unlike a zucchini, it's harvested once, cured, and stored for months rather than picked continuously all summer.
How winter squash fits zone 10's season
Zone 10b's frost-free window runs about 324 days, from January 30 to December 20. Winter Squash needs about 100 days from sowing to first harvest.
Good companions
- Sweet Corn: The classic 'three sisters' pairing. WSU Extension confirms the real mechanism: squash's broad leaves shade the soil, reducing evaporation and inhibiting weed seed germination, while corn stalks give beans (the third sister) something to climb.
Where to buy winter squash seeds
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing winter squash" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 10b calendar · Full companion planting guide · Full plant profile · Plan your beds in the Garden Designer →
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Growing Winter Squash in USDA zone 10b: when to start seeds indoors, when to direct-sow, and when to expect a harvest.
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