When to plant kale in zone 4b — planting calendar

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Showing USDA Zone 4B

Growing SeasonZone 4b

Last frost ~May 15First frost ~Sep 25Today

Start indoorsTransplant / sowHarvestFrost risk

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Start indoors Apr 10 · Sow Apr 24 · First harvest Jun 13 · Wrap by Sep 5

Last spring frostMay 15

Start seeds indoorsApr 10

Direct sowApr 24

First harvestJun 13

Last harvestSep 5

Fall succession sowJul 17

First fall frostSep 25

Why these dates work in zone 4b

Zone 4b's last spring frost averages May 15 and first fall frost Sep 25 — about 133 frost-free days. Kale tolerates light frost, so you can sow ahead of the last-frost date and keep harvesting into the cooler fall. Starting seeds indoors 5 weeks ahead gives strong transplants ready the moment the soil warms. There's also room for a fall succession sowing around Jul 17 for a second harvest before frost.

Common questions

How long does kale take to grow in zone 4b?

Kale matures in about 50–70 days from sowing. In zone 4b that means sowing around Apr 24 and first picking around Jun 13.

Will kale survive frost in zone 4b?

Yes — kale tolerates light frost. In zone 4b you can sow a little before the last frost (around May 15) and keep harvesting past the first fall frost (around Sep 25).

Can I plant a second crop of kale in zone 4b?

Yes — in zone 4b there's time for a fall sowing around Jul 17 for a second harvest before frost.

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