When to plant fennel 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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Sow May 11 · First harvest Jul 15 · Wrap by Sep 9

Last spring frostMay 25

Direct sowMay 11

First harvestJul 15

Last harvestSep 9

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. 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 7 for a second harvest before frost.

Common questions

How long does fennel take to grow in zone 3b?

Fennel matures in about 65–80 days from sowing. In zone 3b that means sowing around May 11 and first picking around Jul 15.

Will fennel survive frost in zone 3b?

Yes — fennel 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 fennel 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 fennel growing guide →