Saint Peter, MN planting zone & frost dates
Saint Peter is in USDA hardiness zone 5a. The last spring frost usually comes around May 2 and the first fall frost around October 4, for a growing season of about 153 days.
Planting calendar for Saint Peter
Dates are counted from the average last spring frost (May 2) 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 7 – Mar 21 Transplant outdoors: May 9 – May 16 |
| Peppers | Start seeds indoors: Feb 21 – Mar 7 Transplant outdoors: May 16 – May 23 |
| Eggplant | Start seeds indoors: Feb 21 – Mar 7 Transplant outdoors: May 16 – May 23 |
| Broccoli | Start seeds indoors: Feb 21 – Mar 7 Transplant outdoors: Apr 4 – Apr 18 |
| Cabbage | Start seeds indoors: Feb 21 – Mar 7 Transplant outdoors: Apr 4 – Apr 18 |
| Onions (sets) | Plant outdoors: Apr 4 – Apr 18 |
| Peas | Sow outdoors: Mar 21 – Apr 4 |
| Spinach | Sow outdoors: Mar 21 – Apr 4 |
| Lettuce | Sow outdoors: Apr 4 – Apr 18 |
| Carrots | Sow outdoors: Apr 4 – Apr 18 |
| Potatoes | Plant outdoors: Apr 4 – Apr 18 |
| Beans | Sow outdoors: May 9 – May 16 |
| Sweet corn | Sow outdoors: May 9 – May 16 |
| Cucumbers | Sow outdoors: May 9 – May 16 |
| Squash & zucchini | Sow outdoors: May 9 – May 16 |
| Basil | Start seeds indoors: Mar 21 – Apr 4 Transplant outdoors: May 9 – May 16 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Aug 9 (8 weeks before the average first fall frost on Oct 4).
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 | Apr 19 | May 2 | May 14 |
| First 32°F frost in fall is before | Oct 16 | Oct 4 | Sep 21 |
How to read it: in spring there is a 10% chance of a frost after May 14, so that is a safe date for tender plants. In fall there is a 10% chance of frost before September 21. A hard freeze (28°F) usually ends around April 22.
Hardiness zone by ZIP code in Saint Peter
- 56082 zone 4b
Nearby cities
- North Mankato zone 5a, last frost Apr 30
- Mankato zone 5a, last frost Apr 30
- New Ulm zone 5a, last frost Apr 29
- Waconia zone 4b, last frost May 5
- Chaska zone 4b, last frost May 5
- Shakopee zone 5a, last frost Apr 23
- Prior Lake zone 4b, last frost Apr 23
- Chanhassen zone 5a, last frost Apr 30
Questions
What growing zone is Saint Peter, MN?
Saint Peter is in USDA Plant Hardiness Zone 5a (average extreme winter low -20°F to -15°F), according to the USDA 2023 map. Some ZIP codes of the city fall in zone 4b.
When is the last frost in Saint Peter?
The average last spring frost (32°F) in Saint Peter is May 2. There is still a 10% chance of frost until May 14.
When can I plant tomatoes in Saint Peter?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around May 9 – May 16. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station St Peter, MN (USC00217405), 0.6 km (0.4 mi) from the city center, elevation 242 m, based on 27 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.