Bozeman, MT planting zone & frost dates
Bozeman is in USDA hardiness zone 5a. The last spring frost usually comes around May 26 and the first fall frost around September 22, for a growing season of about 116 days.
Planting calendar for Bozeman
Dates are counted from the average last spring frost (May 26) using the typical timing recommended by U.S. extension services. Warm-season crops go out only after the danger of frost has passed and the soil has warmed.
| Crop | When |
|---|---|
| Tomatoes | Start seeds indoors: Mar 31 – Apr 14 Transplant outdoors: Jun 2 – Jun 9 |
| Peppers | Start seeds indoors: Mar 17 – Mar 31 Transplant outdoors: Jun 9 – Jun 16 |
| Eggplant | Start seeds indoors: Mar 17 – Mar 31 Transplant outdoors: Jun 9 – Jun 16 |
| Broccoli | Start seeds indoors: Mar 17 – Mar 31 Transplant outdoors: Apr 28 – May 12 |
| Cabbage | Start seeds indoors: Mar 17 – Mar 31 Transplant outdoors: Apr 28 – May 12 |
| Onions (sets) | Plant outdoors: Apr 28 – May 12 |
| Peas | Sow outdoors: Apr 14 – Apr 28 |
| Spinach | Sow outdoors: Apr 14 – Apr 28 |
| Lettuce | Sow outdoors: Apr 28 – May 12 |
| Carrots | Sow outdoors: Apr 28 – May 12 |
| Potatoes | Plant outdoors: Apr 28 – May 12 |
| Beans | Sow outdoors: Jun 2 – Jun 9 |
| Sweet corn | Sow outdoors: Jun 2 – Jun 9 |
| Cucumbers | Sow outdoors: Jun 2 – Jun 9 |
| Squash & zucchini | Sow outdoors: Jun 2 – Jun 9 |
| Basil | Start seeds indoors: Apr 14 – Apr 28 Transplant outdoors: Jun 2 – Jun 9 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Jul 28 (8 weeks before the average first fall frost on Sep 22).
Useful for zone 5a gardens
- Seed starting kit with dome — to start seeds indoors before the last frost
- LED grow light for seedlings — stops leggy seedlings
- Frost cloth / plant covers — for late spring and early fall frosts
- Soil thermometer — warm-season crops need soil above 60°F
- Cold frame / mini greenhouse — adds weeks to a short season
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Frost risk in detail
| 90% chance | 50% chance | 10% chance | |
|---|---|---|---|
| Last 32°F frost in spring is after | May 9 | May 26 | Jun 14 |
| First 32°F frost in fall is before | Oct 5 | Sep 22 | Sep 5 |
How to read it: in spring there is a 10% chance of a frost after June 14, so that is a safe date for tender plants. In fall there is a 10% chance of frost before September 5. A hard freeze (28°F) usually ends around May 8.
Hardiness zone by ZIP code in Bozeman
- 59715 zone 5a
- 59718 zone 5a
- 59719 zone 5a
- 59771 zone 5a
- 59772 zone 5a
Nearby cities
Questions
What growing zone is Bozeman, MT?
Bozeman is in USDA Plant Hardiness Zone 5a (average extreme winter low -20°F to -15°F), according to the USDA 2023 map.
When is the last frost in Bozeman?
The average last spring frost (32°F) in Bozeman is May 26. There is still a 10% chance of frost until June 14.
When can I plant tomatoes in Bozeman?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Jun 2 – Jun 9. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Bozeman Montana State Univ, MT (USC00241044), 2.0 km (1.2 mi) from the city center, elevation 1498 m, based on 30 years of records. Hardiness zone: USDA Plant Hardiness Zone Map 2023 for the ZIP code nearest to the city center. Microclimates (valleys, hills, cities, coasts) can be warmer or colder: check the local forecast before planting. How we calculate the data.