When to plant Cosmos in Zone 6b
In Zone 6b, Cosmos: direct sow outdoors around Apr 15–Apr 29. Expect to harvest around Jun 14–Jun 28.
| Step | When |
|---|---|
| Direct sow outdoors | Apr 15 – Apr 29 |
| Harvest | Jun 14 – Jun 28 |
Tip: Thrives on neglect — too-rich soil gives leaves at the expense of flowers.
Zone 6b averages a last spring frost around Apr 15 and a first fall frost around Oct 25. These are zone averages — look up your ZIP for your exact area.
See the full Zone 6b calendar in the tool →