When to Plant Sweet Corn in Montana
In Montana, the time to sow sweet corn outside runs from May 11 – May 25 in Billings to Jun 20 – Jul 4 in Butte-Silver Bow. In Billings, it's May 11 – May 25. The average last spring frost differs by about 6 weeks across the state (May 4 in Billings, Jun 13 in Butte-Silver Bow), so use the dates for the town nearest you.
Sow corn in blocks rather than single rows so it pollinates well. Wait for soil around 60°F.
- Sow outside: 1–3 weeks after the last frost.
Sweet Corn planting dates in Montana by city
| City | Zone | Sow outside |
|---|---|---|
| Anaconda-Deer Lodge County | 5a | Jun 8 – Jun 22 |
| Belgrade | 5a | Jun 2 – Jun 16 |
| Billings | 5a | May 11 – May 25 |
| Bozeman | 5a | Jun 2 – Jun 16 |
| Butte-Silver Bow | 5a | Jun 20 – Jul 4 |
| Columbia Falls | 5a | Jun 7 – Jun 21 |
| Great Falls | 4b | May 13 – May 27 |
| Hamilton | 5b | May 28 – Jun 11 |
| Havre | 3b | May 22 – Jun 5 |
| Helena | 5a | May 16 – May 30 |
| Kalispell | 5b | Jun 7 – Jun 21 |
| Laurel | 5a | May 12 – May 26 |
| Lewistown | 4b | May 30 – Jun 13 |
| Livingston | 5a | Jun 3 – Jun 17 |
| Miles City | 4b | May 15 – May 29 |
| Missoula | 5b | May 17 – May 31 |
| Polson | 6a | May 17 – May 31 |
| Sidney | 4a | May 18 – Jun 1 |
| Whitefish | 5a | May 23 – Jun 6 |
Calculated from each town's average (50%) frost dates, from the nearest NOAA station (1991–2020). Typical dates for the 2027 planting season, based on NOAA's 1991–2020 averages. They are long-term odds, not a forecast: always check your local forecast before planting. Zones: 2023 USDA Plant Hardiness Zone Map (USDA-ARS and Oregon State University). Not the official map; see planthardiness.ars.usda.gov.
See all frost dates in Montana, or the general guide to when to plant sweet corn.
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