When to plant Rosemary in Zone 3a
In Zone 3a, Rosemary: start seeds indoors around Mar 16–Mar 30; transplant outdoors around Jun 8–Jun 22. Expect to harvest around Sep 6–Sep 20.
| Step | When |
|---|---|
| Start seeds indoors | Mar 16 – Mar 30 |
| Transplant outdoors | Jun 8 – Jun 22 |
| Harvest | Sep 6 – Sep 20 |
Tip: Slow from seed and frost-tender in cold zones — most gardeners start from a plant and overwinter indoors.
Zone 3a averages a last spring frost around May 25 and a first fall frost around Sep 8. These are zone averages — look up your ZIP for your exact area.
See the full Zone 3a calendar in the tool →