Grand Rapids, MN planting zone & frost dates
Grand Rapids is in USDA hardiness zone 4a. The last spring frost usually comes around May 17 and the first fall frost around September 24, for a growing season of about 130 days.
Planting calendar for Grand Rapids
Dates are counted from the average last spring frost (May 17) 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 22 – Apr 5 Transplant outdoors: May 24 – May 31 |
| Peppers | Start seeds indoors: Mar 8 – Mar 22 Transplant outdoors: May 31 – Jun 7 |
| Eggplant | Start seeds indoors: Mar 8 – Mar 22 Transplant outdoors: May 31 – Jun 7 |
| Broccoli | Start seeds indoors: Mar 8 – Mar 22 Transplant outdoors: Apr 19 – May 3 |
| Cabbage | Start seeds indoors: Mar 8 – Mar 22 Transplant outdoors: Apr 19 – May 3 |
| Onions (sets) | Plant outdoors: Apr 19 – May 3 |
| Peas | Sow outdoors: Apr 5 – Apr 19 |
| Spinach | Sow outdoors: Apr 5 – Apr 19 |
| Lettuce | Sow outdoors: Apr 19 – May 3 |
| Carrots | Sow outdoors: Apr 19 – May 3 |
| Potatoes | Plant outdoors: Apr 19 – May 3 |
| Beans | Sow outdoors: May 24 – May 31 |
| Sweet corn | Sow outdoors: May 24 – May 31 |
| Cucumbers | Sow outdoors: May 24 – May 31 |
| Squash & zucchini | Sow outdoors: May 24 – May 31 |
| Basil | Start seeds indoors: Apr 5 – Apr 19 Transplant outdoors: May 24 – May 31 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Jul 30 (8 weeks before the average first fall frost on Sep 24).
Useful for zone 4a 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
As an Amazon Associate, FrostZoneMap earns from qualifying purchases, at no extra cost to you.
Frost risk in detail
| 90% chance | 50% chance | 10% chance | |
|---|---|---|---|
| Last 32°F frost in spring is after | May 3 | May 17 | May 31 |
| First 32°F frost in fall is before | Oct 7 | Sep 24 | Sep 10 |
How to read it: in spring there is a 10% chance of a frost after May 31, so that is a safe date for tender plants. In fall there is a 10% chance of frost before September 10. A hard freeze (28°F) usually ends around May 6.
Hardiness zone by ZIP code in Grand Rapids
- 55730 zone 4a
- 55744 zone 4a
- 55745 zone 4a
Nearby cities
- Hibbing zone 3b, last frost Jun 5
- Brainerd zone 4a, last frost May 8
- Cloquet zone 4a, last frost May 26
- Bemidji zone 3b, last frost May 17
- Duluth zone 4b, last frost May 14
- Sartell zone 4b, last frost May 7
- Sauk Rapids zone 4b, last frost May 7
- Saint Cloud zone 4b, last frost May 7
Questions
What growing zone is Grand Rapids, MN?
Grand Rapids is in USDA Plant Hardiness Zone 4a (average extreme winter low -30°F to -25°F), according to the USDA 2023 map.
When is the last frost in Grand Rapids?
The average last spring frost (32°F) in Grand Rapids is May 17. There is still a 10% chance of frost until May 31.
When can I plant tomatoes in Grand Rapids?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around May 24 – May 31. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Grand Rpds Forest Lab, MN (USC00213303), 2.6 km (1.6 mi) from the city center, elevation 399 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.