When to plant onions in zone 4
In USDA zone 4, the last spring frost usually falls between May 1 and May 20. Start onions indoors around Feb 19 to Mar 22. Plant them out around May 3 to May 28. Expect to harvest around Sep 2 to Oct 9.
Zone 4 dates for onions
| Start seeds indoors | Feb 19 to Mar 22 |
|---|---|
| Plant outside | May 3 to May 28 |
| Harvest | Sep 2 to Oct 9 |
| Typical last spring frost | May 1 to May 20 |
| 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 onions in your exact town, not just your zone.
Get my dates free →How to grow onions
Plant once, season everything all year. Read the full onions growing guide: spacing, sun and soil, step-by-step care, problems and the best varieties.