When to plant swiss chard 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 27 · Sow May 11 · First harvest Jun 30 · Wrap by Sep 15

Last spring frostMay 25

Start seeds indoorsApr 27

Direct sowMay 11

First harvestJun 30

Last harvestSep 15

Fall succession sowJul 7

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. Swiss Chard tolerates light frost, so you can sow 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 7 for a second harvest before frost.

Common questions

How long does swiss chard take to grow in zone 3b?

Swiss Chard matures in about 50–60 days from sowing. In zone 3b that means sowing around May 11 and first picking around Jun 30.

Will swiss chard survive frost in zone 3b?

Yes — swiss chard tolerates light frost. In zone 3b you can sow 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 swiss chard in zone 3b?

Yes — in zone 3b there's time for a fall sowing around Jul 7 for a second harvest before frost.

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