When to plant radish 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

APRMAYJUN

Sow Apr 17 · First harvest May 9 · Wrap by May 23

Last spring frostMay 15

Direct sowApr 17

First harvestMay 9

Last harvestMay 23

Fall succession sowAug 14

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. Radish tolerates light frost, so you can sow ahead of the last-frost date and keep harvesting into the cooler fall. There's also room for a fall succession sowing around Aug 14 for a second harvest before frost.

Common questions

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

Radish matures in about 22–30 days from sowing. In zone 4b that means sowing around Apr 17 and first picking around May 9.

Will radish survive frost in zone 4b?

Yes — radish 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 radish in zone 4b?

Yes — in zone 4b there's time for a fall sowing around Aug 14 for a second harvest before frost.

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