When to plant Brussels Sprouts in Zone 4a
In Zone 4a, Brussels Sprouts: start seeds indoors around Apr 3–Apr 17; transplant outdoors around May 8–May 22. Expect to harvest around Aug 16–Aug 30.
| Step | When |
|---|---|
| Start seeds indoors | Apr 3 – Apr 17 |
| Transplant outdoors | May 8 – May 22 |
| Harvest | Aug 16 – Aug 30 |
Tip: A long-season crop best for fall — the sprouts sweeten after a frost or two.
Zone 4a averages a last spring frost around May 15 and a first fall frost around Sep 18. These are zone averages — look up your ZIP for your exact area.
See the full Zone 4a calendar in the tool →