When to plant Dahlia in Zone 5a
In Zone 5a, Dahlia: start seeds indoors around Apr 7–Apr 21; transplant outdoors around May 12–May 19. Expect to harvest around Aug 20–Aug 27.
| Step | When |
|---|---|
| Start seeds indoors | Apr 7 – Apr 21 |
| Transplant outdoors | May 12 – May 19 |
| Harvest | Aug 20 – Aug 27 |
Tip: Plant tubers after frost. In cold zones, lift and store them indoors over winter.
Zone 5a averages a last spring frost around May 5 and a first fall frost around Oct 1. These are zone averages — look up your ZIP for your exact area.
See the full Zone 5a calendar in the tool →