Last spring frostMay 7
Start seeds indoorsFeb 12
Transplant outApr 23
First harvestAug 1
Last harvestSep 26
First fall frostOct 13
Why these dates work in zone 4a
Zone 4a's last spring frost averages May 7 and first fall frost Oct 13 — about 159 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 4a?
Leek matures in about 100–120 days from transplanting. In zone 4a that means setting plants out around Apr 23 and first picking around Aug 1.
Will leek survive frost in zone 4a?
Yes — leek tolerates light frost. In zone 4a you can set plants out a little before the last frost (around May 7) and keep harvesting past the first fall frost (around Oct 13).
For soil, spacing, pests and companion planting, see the full leek growing guide →