Last spring frostMay 6
Start seeds indoorsApr 15
Direct sowMay 13
First harvestJun 27
Last harvestSep 5
First fall frostOct 22
Why these dates work in zone 3b
Zone 3b's last spring frost averages May 6 and first fall frost Oct 22 — about 169 frost-free days. Zucchini is frost-sensitive, so the 1w after frost timing builds in a safety margin against a late cold snap — setting plants out too early risks losing them to frost. Starting seeds indoors 3 weeks ahead gives strong transplants ready the moment the soil warms.
Common questions
How long does zucchini take to grow in zone 3b?
Zucchini matures in about 45–60 days from sowing. In zone 3b that means sowing around May 13 and first picking around Jun 27.
Will zucchini survive frost in zone 3b?
No — zucchini is frost-sensitive. In zone 3b, wait until after the last frost (around May 6) to plant, and harvest before the first fall frost (around Oct 22).
For soil, spacing, pests and companion planting, see the full zucchini growing guide →