When to plant Thyme in Zone 4a
In Zone 4a, Thyme: start seeds indoors around Mar 20–Apr 3; transplant outdoors around May 15–May 29. Expect to harvest around Aug 3–Aug 17.
| Step | When |
|---|---|
| Start seeds indoors | Mar 20 – Apr 3 |
| Transplant outdoors | May 15 – May 29 |
| Harvest | Aug 3 – Aug 17 |
Tip: Perennial in most zones. Loves lean, well-drained soil — don't overwater or overfeed.
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 →