When to plant cassava in Montana
Montana spans USDA zones 4b–5b, so the right time to plant cassava 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 – June 1 |
| Missoula | 5b | May 10 | October 1 | May 24 – June 7 |
| Great Falls | 4b | May 6 | October 1 | May 20 – June 3 |
| Bozeman | 5a | May 26 | September 22 | June 9 – June 23 |
| Butte-Silver Bow | 5a | June 13 | September 5 | June 27 – July 11 |
| Helena | 5a | May 9 | September 30 | May 23 – June 6 |
| Kalispell | 5b | May 31 | September 10 | June 14 – June 28 |
| Belgrade | 5a | May 26 | September 16 | June 9 – June 23 |
Cassava in Montana: FAQ
When can I plant cassava in Montana?
Across Montana, the time to transplant cassava spans roughly May 18 in Billings to June 27 in Butte-Silver Bow, each following that city's local frost dates.
Does the cassava planting date vary across Montana?
Yes. Montana publishes 8 cities with their own frost dates, so the right cassava 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 cassava take to grow in Montana?
Cassava takes about 240–300 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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