Plant Zucchini in Zone 10a
Seed-starting, transplant & harvest dates for USDA Zone 10a
Zone 10a averages 323 frost-free days, running from a last spring frost around January 31 to a first fall frost around December 20. Zucchini needs roughly 55 days from planting out to first harvest, so it uses about 17 percent of that window. Zucchini is a tender crop, which is what decides where in the window it belongs.
Because zucchini needs a head start, sow seed indoors around Jan 10, about 3 weeks ahead of the Zone 10a last frost. Transplants go out around Feb 14. Starting earlier than that in Zone 10a usually backfires: plants outgrow their cells and stall when they finally hit cold soil. At 55 days to harvest, a 323-day Zone 10a season has room for about 4 sowings, so stagger them rather than planting everything at once.
Planting zucchini for a fall harvest in Zone 10a
Yes. Sow zucchini by September 28 in Zone 10a. That is 83 days before the average first frost, which covers the 55 days to maturity plus about two weeks for the slower growth that comes with shortening days, plus a two week margin because frost kills zucchini outright.
One midsummer sowing of zucchini replaces the spring plants right as squash vine borer takes them out.
Fall dates are counted backward from the Zone 10a average first frost, not forward from a sowing date. See the fall planting calendar by zone for the full method.
Spring vs fall zucchini in Zone 10a
| Planting | Sow or start | In the ground | Harvest |
|---|---|---|---|
| Spring | Jan 10 | Feb 14 | Apr 10 |
| Fall | by Sep 28 | Sep 28 | Nov 22 |
Zucchini in nearby zones
Further reading on zucchini
- When to start seeds indoors by zone
Indoor start dates for zucchini, counted back from your last frost.
- Hardening off seedlings: a schedule
A day by day plan for moving zucchini seedlings outdoors.
- Best grow lights for seed starting
What light seedlings actually need, and which fixtures deliver it.
Other crops in Zone 10a
Frequently asked questions
When should I start zucchini in Zone 10a?
Start zucchini seeds indoors around Jan 10 (Zone 10a).
Can I direct sow zucchini in Zone 10a?
Yes, direct sow around Feb 14.
Can I plant zucchini in the fall in Zone 10a?
Yes. Sow zucchini by September 28 in Zone 10a. That is 83 days before the average first frost, which covers the 55 days to maturity plus about two weeks for the slower growth that comes with shortening days, plus a two week margin because frost kills zucchini outright.
Will zucchini survive frost in Zone 10a?
No. Zucchini is a tender crop and a single light frost ends it, so every Zone 10a planting has to finish before the average first frost.
How many plantings of zucchini fit in a Zone 10a season?
About 4. Zone 10a averages 323 frost-free days and zucchini needs roughly 55 days plus a couple of weeks of turnaround, so sowing every 35 days keeps a supply coming.