When to plant garlic in Montana
Montana spans USDA zones 4b–5b, so the right time to plant garlic shifts by weeks across the state. The window to plant for fall/overwintering runs from about August 8 in Butte-Silver Bow to September 9 in Billings — below are local dates for 8 cities, each computed from its own frost dates.
| City | Zone | Last frost | First frost | Fall-plant |
|---|---|---|---|---|
| Billings | 5a | May 4 | October 7 | September 9 – September 23 |
| Missoula | 5b | May 10 | October 1 | September 3 – September 17 |
| Great Falls | 4b | May 6 | October 1 | September 3 – September 17 |
| Bozeman | 5a | May 26 | September 22 | August 25 – September 8 |
| Butte-Silver Bow | 5a | June 13 | September 5 | August 8 – August 22 |
| Helena | 5a | May 9 | September 30 | September 2 – September 16 |
| Kalispell | 5b | May 31 | September 10 | August 13 – August 27 |
| Belgrade | 5a | May 26 | September 16 | August 19 – September 2 |
Garlic in Montana: FAQ
When can I plant garlic in Montana?
Across Montana, the time to fall-plant garlic spans roughly August 8 in Butte-Silver Bow to September 9 in Billings, each following that city's local frost dates.
Does the garlic planting date vary across Montana?
Yes. Montana publishes 8 cities with their own frost dates, so the right garlic planting window shifts by weeks between the warmest and coldest parts of the state — use your city's page for the exact dates.
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