When to plant bok choy in zone 4a — planting calendar

Not your zone?

Showing USDA Zone 4A

Growing SeasonZone 4a

Last frost ~May 20First frost ~Sep 20Today

Start indoorsTransplant / sowHarvestFrost risk

APRMAYJUNJUL

Start indoors Apr 22 · Transplant Apr 29 · First harvest Jun 13 · Wrap by Jul 4

Last spring frostMay 20

Start seeds indoorsApr 22

Transplant outApr 29

First harvestJun 13

Last harvestJul 4

Fall succession sowJul 26

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. Bok Choy 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 4 weeks ahead gives strong transplants ready the moment the soil warms. There's also room for a fall succession sowing around Jul 26 for a second harvest before frost.

Common questions

How long does bok choy take to grow in zone 4a?

Bok Choy matures in about 45–60 days from transplanting. In zone 4a that means setting plants out around Apr 29 and first picking around Jun 13.

Will bok choy survive frost in zone 4a?

Yes — bok choy 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 bok choy in zone 4a?

Yes — in zone 4a there's time for a fall sowing around Jul 26 for a second harvest before frost.

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