When to plant sunflower in Iowa
Iowa spans USDA zones 5a–6a, so the right time to plant sunflower shifts by weeks across the state. The window to sow seed directly outdoors runs from about April 12 in Fort Madison to May 1 in Spencer — below are local dates for 42 cities, each computed from its own frost dates.
| City | Zone | Last frost | First frost | Direct sow |
|---|---|---|---|---|
| Des Moines | 5b | April 18 | October 20 | April 18 – May 9 |
| Cedar Rapids | 5b | April 27 | October 11 | April 27 – May 18 |
| Davenport | 5b | April 19 | October 22 | April 19 – May 10 |
| Sioux City | 5a | April 29 | October 7 | April 29 – May 20 |
| Iowa City | 5b | April 21 | October 18 | April 21 – May 12 |
| Ankeny | 5b | April 23 | October 15 | April 23 – May 14 |
| West Des Moines | 5b | April 18 | October 20 | April 18 – May 9 |
| Ames | 5b | April 26 | October 8 | April 26 – May 17 |
Sunflower in Iowa: FAQ
When can I plant sunflower in Iowa?
Across Iowa, the time to direct-sow sunflower spans roughly April 12 in Fort Madison to May 1 in Spencer, each following that city's local frost dates.
Does the sunflower planting date vary across Iowa?
Yes. Iowa publishes 42 cities with their own frost dates, so the right sunflower planting window shifts by weeks between the warmest and coldest parts of the state — use your city's page for the exact dates.
How long does sunflower take to grow in Iowa?
Sunflower takes about 70–100 days to reach harvest once planted — check that this fits inside your city's frost-free season on its place page.
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