When to plant broccoli in zone 3b — planting calendar

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Showing USDA Zone 3B

Growing SeasonZone 3b

Last frost ~May 25First frost ~Sep 15Today

Start indoorsTransplant / sowHarvestFrost risk

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Start indoors Apr 13 · Transplant May 4 · First harvest Jul 23 · Wrap by Aug 20

Last spring frostMay 25

Start seeds indoorsApr 13

Transplant outMay 4

First harvestJul 23

Last harvestAug 20

Fall succession sowJun 16

First fall frostSep 15

Why these dates work in zone 3b

Zone 3b's last spring frost averages May 25 and first fall frost Sep 15 — about 113 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 16 for a second harvest before frost.

Common questions

How long does broccoli take to grow in zone 3b?

Broccoli matures in about 80–100 days from transplanting. In zone 3b that means setting plants out around May 4 and first picking around Jul 23.

Will broccoli survive frost in zone 3b?

Yes — broccoli tolerates light frost. In zone 3b you can set plants out a little before the last frost (around May 25) and keep harvesting past the first fall frost (around Sep 15).

Can I plant a second crop of broccoli in zone 3b?

Yes — in zone 3b there's time for a fall sowing around Jun 16 for a second harvest before frost.

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