When to plant Dahlia in Zone 3a
In Zone 3a, Dahlia: start seeds indoors around Apr 27–May 11; transplant outdoors around Jun 1–Jun 8. Expect to harvest around Sep 9–Sep 16.
| Step | When |
|---|---|
| Start seeds indoors | Apr 27 – May 11 |
| Transplant outdoors | Jun 1 – Jun 8 |
| Harvest | Sep 9 – Sep 16 |
Tip: Plant tubers after frost. In cold zones, lift and store them indoors over winter.
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 →