Plant Zucchini in Zone 3a
Seed-starting, transplant & harvest dates for USDA Zone 3a
Zone 3a averages 123 frost-free days, running from a last spring frost around May 15 to a first fall frost around September 15. Zucchini needs roughly 55 days from planting out to first harvest, so it uses about 45 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 Apr 24, about 3 weeks ahead of the Zone 3a last frost. Transplants go out around May 29. Starting earlier than that in Zone 3a usually backfires: plants outgrow their cells and stall when they finally hit cold soil.
Fall planting: zucchini in Zone 3a
Zucchini has no useful fall window in Zone 3a. One midsummer sowing of zucchini replaces the spring plants right as squash vine borer takes them out.
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 3a 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 3a
| Planting | Sow or start | In the ground | Harvest |
|---|---|---|---|
| Spring | Apr 24 | May 29 | Jul 23 |
| Fall | — | — | — |
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 3a
Frequently asked questions
When should I start zucchini in Zone 3a?
Start zucchini seeds indoors around Apr 24 (Zone 3a).
Can I direct sow zucchini in Zone 3a?
Yes, direct sow around May 29.
Can I plant zucchini in the fall in Zone 3a?
Zucchini has no useful fall window in Zone 3a. One midsummer sowing of zucchini replaces the spring plants right as squash vine borer takes them out.
Will zucchini survive frost in Zone 3a?
No. Zucchini is a tender crop and a single light frost ends it, so every Zone 3a planting has to finish before the average first frost.