When to plant Dahlia in Zone 1a
In Zone 1a, Dahlia: start seeds indoors around May 18–Jun 1; transplant outdoors around Jun 22–Jun 29. Expect to harvest around Sep 30–Oct 7.
| Step | When |
|---|---|
| Start seeds indoors | May 18 – Jun 1 |
| Transplant outdoors | Jun 22 – Jun 29 |
| Harvest | Sep 30 – Oct 7 |
Tip: Plant tubers after frost. In cold zones, lift and store them indoors over winter.
Zone 1a averages a last spring frost around Jun 15 and a first fall frost around Aug 15. These are zone averages — look up your ZIP for your exact area.
See the full Zone 1a calendar in the tool →