When to plant onion in zone 7b — planting calendar

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Showing USDA Zone 7B

Growing SeasonZone 7b

Last frost ~Apr 5First frost ~Nov 1Today

Start indoorsTransplant / sowHarvestFrost risk

JANFEBMARAPRMAYJUNJUL

Start indoors Jan 25 · Sow Mar 22 · First harvest Jun 20 · Wrap by Jul 18

Last spring frostApr 5

Start seeds indoorsJan 25

Direct sowMar 22

First harvestJun 20

Last harvestJul 18

First fall frostNov 1

Why these dates work in zone 7b

Zone 7b's last spring frost averages Apr 5 and first fall frost Nov 1 — about 210 frost-free days. Onion tolerates light frost, so you can sow ahead of the last-frost date and keep harvesting into the cooler fall. Starting seeds indoors 10 weeks ahead gives strong transplants ready the moment the soil warms.

Common questions

How long does onion take to grow in zone 7b?

Onion matures in about 90–110 days from sowing. In zone 7b that means sowing around Mar 22 and first picking around Jun 20.

Will onion survive frost in zone 7b?

Yes — onion tolerates light frost. In zone 7b you can sow a little before the last frost (around Apr 5) and keep harvesting past the first fall frost (around Nov 1).

For soil, spacing, pests and companion planting, see the full onion growing guide →