Stillwater, MN planting zone & frost dates
Stillwater is in USDA hardiness zone 4b. The last spring frost usually comes around April 22 and the first fall frost around October 19, for a growing season of about 178 days.
Planting calendar for Stillwater
Dates are counted from the average last spring frost (April 22) 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: Feb 25 – Mar 11 Transplant outdoors: Apr 29 – May 6 |
| Peppers | Start seeds indoors: Feb 11 – Feb 25 Transplant outdoors: May 6 – May 13 |
| Eggplant | Start seeds indoors: Feb 11 – Feb 25 Transplant outdoors: May 6 – May 13 |
| Broccoli | Start seeds indoors: Feb 11 – Feb 25 Transplant outdoors: Mar 25 – Apr 8 |
| Cabbage | Start seeds indoors: Feb 11 – Feb 25 Transplant outdoors: Mar 25 – Apr 8 |
| Onions (sets) | Plant outdoors: Mar 25 – Apr 8 |
| Peas | Sow outdoors: Mar 11 – Mar 25 |
| Spinach | Sow outdoors: Mar 11 – Mar 25 |
| Lettuce | Sow outdoors: Mar 25 – Apr 8 |
| Carrots | Sow outdoors: Mar 25 – Apr 8 |
| Potatoes | Plant outdoors: Mar 25 – Apr 8 |
| Beans | Sow outdoors: Apr 29 – May 6 |
| Sweet corn | Sow outdoors: Apr 29 – May 6 |
| Cucumbers | Sow outdoors: Apr 29 – May 6 |
| Squash & zucchini | Sow outdoors: Apr 29 – May 6 |
| Basil | Start seeds indoors: Mar 11 – Mar 25 Transplant outdoors: Apr 29 – May 6 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Aug 24 (8 weeks before the average first fall frost on Oct 19).
Useful for zone 4b 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 7 | Apr 22 | May 6 |
| First 32°F frost in fall is before | Nov 3 | Oct 19 | Oct 3 |
How to read it: in spring there is a 10% chance of a frost after May 6, so that is a safe date for tender plants. In fall there is a 10% chance of frost before October 3. A hard freeze (28°F) usually ends around April 12.
Hardiness zone by ZIP code in Stillwater
- 55082 zone 4b
- 55083 zone 5a
Nearby cities
- Oakdale zone 5a, last frost Apr 26
- North Saint Paul zone 5a, last frost Apr 26
- Woodbury zone 5a, last frost Apr 26
- White Bear Lake zone 5a, last frost Apr 23
- Hugo zone 4b, last frost Apr 23
- Maplewood zone 5a, last frost Apr 26
- Cottage Grove zone 5a, last frost Apr 23
- Vadnais Heights zone 5a, last frost Apr 23
Questions
What growing zone is Stillwater, MN?
Stillwater is in USDA Plant Hardiness Zone 4b (average extreme winter low -25°F to -20°F), according to the USDA 2023 map. Some ZIP codes of the city fall in zone 5a.
When is the last frost in Stillwater?
The average last spring frost (32°F) in Stillwater is April 22. There is still a 10% chance of frost until May 6.
When can I plant tomatoes in Stillwater?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Apr 29 – May 6. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Stillwater 1 Se, MN (USC00218037), 1.8 km (1.1 mi) from the city center, elevation 216 m, based on 13 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.