In USDA zone 3, the last spring frost usually falls between May 5 and May 31. Start leeks indoors around Feb 26 to Mar 29. Plant them out around May 16 to Jun 10. Expect to harvest around Oct 13 to Oct 31.
| Start seeds indoors | Feb 26 to Mar 29 |
|---|---|
| Plant outside | May 16 to Jun 10 |
| Harvest | Oct 13 to Oct 31 |
| Typical last spring frost | May 5 to May 31 |
| Typical first fall frost | around Sep 15 |
USDA zones measure winter cold, not frost dates, so these are typical dates for the zone. Towns in the same zone can be weeks apart.
Get dates for leeks in your exact town, not just your zone.
Get my dates free →Mild, hardy alliums that stand through winter. Read the full leeks growing guide: spacing, sun and soil, step-by-step care, problems and the best varieties.