Last spring frostMay 6
Start seeds indoorsFeb 11
Transplant outApr 22
First harvestJul 31
Last harvestSep 25
First fall frostOct 22
Why these dates work in zone 3b
Zone 3b's last spring frost averages May 6 and first fall frost Oct 22 — about 169 frost-free days. Leek tolerates light frost, so you can set plants out ahead of the last-frost date and keep harvesting into the cooler fall. Starting seeds indoors 12 weeks ahead gives strong transplants ready the moment the soil warms.
Common questions
How long does leek take to grow in zone 3b?
Leek matures in about 100–120 days from transplanting. In zone 3b that means setting plants out around Apr 22 and first picking around Jul 31.
Will leek survive frost in zone 3b?
Yes — leek tolerates light frost. In zone 3b you can set plants out a little before the last frost (around May 6) and keep harvesting past the first fall frost (around Oct 22).
For soil, spacing, pests and companion planting, see the full leek growing guide →