When to plant broccoli in zone 4a — planting calendar

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Showing USDA Zone 4A

Growing SeasonZone 4a

Last frost ~May 20First frost ~Sep 20Today

Start indoorsTransplant / sowHarvestFrost risk

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Start indoors Apr 8 · Transplant Apr 29 · First harvest Jul 18 · Wrap by Aug 15

Last spring frostMay 20

Start seeds indoorsApr 8

Transplant outApr 29

First harvestJul 18

Last harvestAug 15

Fall succession sowJun 21

First fall frostSep 20

Why these dates work in zone 4a

Zone 4a's last spring frost averages May 20 and first fall frost Sep 20 — about 123 frost-free days. Broccoli tolerates light frost, so you can set plants out ahead of the last-frost date and keep harvesting into the cooler fall. Starting seeds indoors 6 weeks ahead gives strong transplants ready the moment the soil warms. There's also room for a fall succession sowing around Jun 21 for a second harvest before frost.

Common questions

How long does broccoli take to grow in zone 4a?

Broccoli matures in about 80–100 days from transplanting. In zone 4a that means setting plants out around Apr 29 and first picking around Jul 18.

Will broccoli survive frost in zone 4a?

Yes — broccoli tolerates light frost. In zone 4a you can set plants out a little before the last frost (around May 20) and keep harvesting past the first fall frost (around Sep 20).

Can I plant a second crop of broccoli in zone 4a?

Yes — in zone 4a there's time for a fall sowing around Jun 21 for a second harvest before frost.

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