When to plant Broccoli in Zone 4a
In Zone 4a, Broccoli: start seeds indoors around Mar 27–Apr 10; transplant outdoors around May 1–May 15; direct sow outdoors around Jun 12–Jul 3. Expect to harvest around Jul 5–Jul 19.
| Step | When |
|---|---|
| Start seeds indoors | Mar 27 – Apr 10 |
| Transplant outdoors | May 1 – May 15 |
| Direct sow outdoors | Jun 12 – Jul 3 |
| Harvest | Jul 5 – Jul 19 |
| Harvest | Aug 16 – Sep 6 |
Tip: A cool-season brassica. Transplant in early spring or late summer; it bolts in midsummer heat.
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 →