When to plant fennel 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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Sow May 6 · First harvest Jul 10 · Wrap by Sep 4

Last spring frostMay 20

Direct sowMay 6

First harvestJul 10

Last harvestSep 4

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. Fennel 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 Jul 12 for a second harvest before frost.

Common questions

How long does fennel take to grow in zone 4a?

Fennel matures in about 65–80 days from sowing. In zone 4a that means sowing around May 6 and first picking around Jul 10.

Will fennel survive frost in zone 4a?

Yes — fennel 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 fennel 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 fennel growing guide →