When to plant Cosmos in Zone 8a
In Zone 8a, Cosmos: direct sow outdoors around Mar 22–Apr 5. Expect to harvest around May 21–Jun 4.
| Step | When |
|---|---|
| Direct sow outdoors | Mar 22 – Apr 5 |
| Harvest | May 21 – Jun 4 |
Tip: Thrives on neglect — too-rich soil gives leaves at the expense of flowers.
Zone 8a averages a last spring frost around Mar 22 and a first fall frost around Nov 18. These are zone averages — look up your ZIP for your exact area.
See the full Zone 8a calendar in the tool →