When to plant swiss chard in zone 4a — planting calendar

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Showing USDA Zone 4A

Growing SeasonZone 4a

Last frost ~May 20First frost ~Sep 20Today

Start indoorsTransplant / sowHarvestFrost risk

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Start indoors Apr 22 · Sow May 6 · First harvest Jun 25 · Wrap by Sep 20

Last spring frostMay 20

Start seeds indoorsApr 22

Direct sowMay 6

First harvestJun 25

Last harvestSep 20

Fall succession sowJul 12

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. 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 12 for a second harvest before frost.

Common questions

How long does swiss chard take to grow in zone 4a?

Swiss Chard matures in about 50–60 days from sowing. In zone 4a that means sowing around May 6 and first picking around Jun 25.

Will swiss chard survive frost in zone 4a?

Yes — swiss chard tolerates light frost. In zone 4a you can sow 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 swiss chard in zone 4a?

Yes — in zone 4a there's time for a fall sowing around Jul 12 for a second harvest before frost.

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