When to plant Broccoli in Zone 4b
In Zone 4b, Broccoli: start seeds indoors around Mar 22–Apr 5; transplant outdoors around Apr 26–May 10; direct sow outdoors around Jun 16–Jul 7. Expect to harvest around Jun 30–Jul 14.
| Step | When |
|---|---|
| Start seeds indoors | Mar 22 – Apr 5 |
| Transplant outdoors | Apr 26 – May 10 |
| Direct sow outdoors | Jun 16 – Jul 7 |
| Harvest | Jun 30 – Jul 14 |
| Harvest | Aug 20 – Sep 10 |
Tip: A cool-season brassica. Transplant in early spring or late summer; it bolts in midsummer heat.
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 →