When to plant sunflower in Montana
Montana spans USDA zones 4b–5b, so the right time to plant sunflower shifts by weeks across the state. The window to sow seed directly outdoors runs from about May 4 in Billings to June 13 in Butte-Silver Bow — below are local dates for 8 cities, each computed from its own frost dates.
| City | Zone | Last frost | First frost | Direct sow |
|---|---|---|---|---|
| Billings | 5a | May 4 | October 7 | May 4 – May 25 |
| Missoula | 5b | May 10 | October 1 | May 10 – May 31 |
| Great Falls | 4b | May 6 | October 1 | May 6 – May 27 |
| Bozeman | 5a | May 26 | September 22 | May 26 – June 16 |
| Butte-Silver Bow | 5a | June 13 | September 5 | June 13 – July 4 |
| Helena | 5a | May 9 | September 30 | May 9 – May 30 |
| Kalispell | 5b | May 31 | September 10 | May 31 – June 21 |
| Belgrade | 5a | May 26 | September 16 | May 26 – June 16 |
Sunflower in Montana: FAQ
When can I plant sunflower in Montana?
Across Montana, the time to direct-sow sunflower spans roughly May 4 in Billings to June 13 in Butte-Silver Bow, each following that city's local frost dates.
Does the sunflower planting date vary across Montana?
Yes. Montana publishes 8 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 Montana?
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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