When to plant Brussels Sprouts in Zone 4b
In Zone 4b, Brussels Sprouts: start seeds indoors around Mar 29–Apr 12; transplant outdoors around May 3–May 17. Expect to harvest around Aug 11–Aug 25.
| Step | When |
|---|---|
| Start seeds indoors | Mar 29 – Apr 12 |
| Transplant outdoors | May 3 – May 17 |
| Harvest | Aug 11 – Aug 25 |
Tip: A long-season crop best for fall — the sprouts sweeten after a frost or two.
Zone 4b averages a last spring frost around May 10 and a first fall frost around Sep 22. These are zone averages — look up your ZIP for your exact area.
See the full Zone 4b calendar in the tool →