When to plant Zinnia in Zone 4b
In Zone 4b, Zinnia: start seeds indoors around Apr 12–Apr 26; transplant outdoors around May 17–May 24; direct sow outdoors around May 10–May 24. Expect to harvest around Jul 9–Jul 23.
| Step | When |
|---|---|
| Start seeds indoors | Apr 12 – Apr 26 |
| Transplant outdoors | May 17 – May 24 |
| Direct sow outdoors | May 10 – May 24 |
| Harvest | Jul 9 – Jul 23 |
| Harvest | Jul 16 – Jul 23 |
Tip: A cut-flower workhorse. Direct-sow after frost and pinch young plants for more stems.
Zone 4b averages a last spring frost around May 10 and a first fall frost around Sep 22. These are zone averages — look up your ZIP for your exact area.
See the full Zone 4b calendar in the tool →