When to plant basil in Montana
Montana spans USDA zones 4b–5b, so the right time to plant basil shifts by weeks across the state. The window to transplant seedlings outdoors runs from about May 18 in Billings to June 27 in Butte-Silver Bow — below are local dates for 8 cities, each computed from its own frost dates.
| City | Zone | Last frost | First frost | Transplant out |
|---|---|---|---|---|
| Billings | 5a | May 4 | October 7 | May 18 – May 25 |
| Missoula | 5b | May 10 | October 1 | May 24 – May 31 |
| Great Falls | 4b | May 6 | October 1 | May 20 – May 27 |
| Bozeman | 5a | May 26 | September 22 | June 9 – June 16 |
| Butte-Silver Bow | 5a | June 13 | September 5 | June 27 – July 4 |
| Helena | 5a | May 9 | September 30 | May 23 – May 30 |
| Kalispell | 5b | May 31 | September 10 | June 14 – June 21 |
| Belgrade | 5a | May 26 | September 16 | June 9 – June 16 |
Basil in Montana: FAQ
When can I plant basil in Montana?
Across Montana, the time to transplant basil spans roughly May 18 in Billings to June 27 in Butte-Silver Bow, each following that city's local frost dates.
Does the basil planting date vary across Montana?
Yes. Montana publishes 8 cities with their own frost dates, so the right basil 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 basil take to grow in Montana?
Basil takes about 60–75 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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