When to plant fennel in zone 4b — planting calendar

Not your zone?

Showing USDA Zone 4B

Growing SeasonZone 4b

Last frost ~May 15First frost ~Sep 25Today

Start indoorsTransplant / sowHarvestFrost risk

APRMAYJUNJULAUGSEP

Sow May 1 · First harvest Jul 5 · Wrap by Aug 30

Last spring frostMay 15

Direct sowMay 1

First harvestJul 5

Last harvestAug 30

Fall succession sowJul 17

First fall frostSep 25

Why these dates work in zone 4b

Zone 4b's last spring frost averages May 15 and first fall frost Sep 25 — about 133 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 17 for a second harvest before frost.

Common questions

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

Fennel matures in about 65–80 days from sowing. In zone 4b that means sowing around May 1 and first picking around Jul 5.

Will fennel survive frost in zone 4b?

Yes — fennel tolerates light frost. In zone 4b you can sow a little before the last frost (around May 15) and keep harvesting past the first fall frost (around Sep 25).

Can I plant a second crop of fennel in zone 4b?

Yes — in zone 4b there's time for a fall sowing around Jul 17 for a second harvest before frost.

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