State growing guide
Montana Planting Guide
USDA Zone 4a/4b · Last frost May 20 · First frost Sep 15 · 118 days
Zone-specific planting calendar, major city frost dates, top crops, and Duke's tips for growing food in Montana.
Frost Dates by City — Montana
Average frost dates for major Montana cities. Use these to calculate your indoor start dates and transplant windows.
| City | USDA Zone | Last Spring Frost | First Fall Frost | Tomato Transplant Window |
|---|---|---|---|---|
| Billings | 4b | May 20 | Sep 18 | ~2 wks after (May 20) |
| Great Falls | 4b | May 20 | Sep 18 | ~2 wks after (May 20) |
| Missoula | 5a | May 12 | Sep 28 | ~2 wks after (May 12) |
| Bozeman | 4b | May 22 | Sep 12 | ~2 wks after (May 22) |
| Helena | 5a | May 15 | Sep 25 | ~2 wks after (May 15) |
Average dates based on 30-year NOAA climate normals. Individual years may vary ±2 weeks. Use the Zone Lookup Tool for ZIP-specific dates.
Duke's Top Tips for Montana Gardeners
- Missoula and the western valleys have longer seasons than eastern Montana
- Use Wall O' Waters to plant tomatoes 4–5 weeks before last frost date
- Short-season varieties are mandatory — choose under 65 days for tomatoes
- Hoop tunnels or greenhouses are game-changers for Montana gardeners
Common Challenges in Montana
- ⚠ Very short growing season (100–120 days)
- ⚠ May and September can have damaging frosts
- ⚠ Wind is extreme across eastern Montana — windbreaks essential
Best Crops for Montana
Potatoes Wheat Barley Kale Carrots Beets Peas Lettuce Short-Season Tomatoes
Get exact dates for your ZIP code in Montana
City averages are a starting point. Your actual microclimate matters — enter your ZIP for precise frost dates.
Frequently Asked Questions — Montana Gardening
What zone is Montana?
Montana is primarily Zones 3–5. Billings and Great Falls are Zone 4b, Missoula and Helena are Zone 5a, and the isolated valleys of western Montana reach Zone 6a.