Marinette, WI planting zone & frost dates
Marinette is in USDA hardiness zone 5b. The last spring frost usually comes around May 4 and the first fall frost around October 11, for a growing season of about 160 days.
Planting calendar for Marinette
Dates are counted from the average last spring frost (May 4) 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 9 – Mar 23 Transplant outdoors: May 11 – May 18 |
| Peppers | Start seeds indoors: Feb 23 – Mar 9 Transplant outdoors: May 18 – May 25 |
| Eggplant | Start seeds indoors: Feb 23 – Mar 9 Transplant outdoors: May 18 – May 25 |
| Broccoli | Start seeds indoors: Feb 23 – Mar 9 Transplant outdoors: Apr 6 – Apr 20 |
| Cabbage | Start seeds indoors: Feb 23 – Mar 9 Transplant outdoors: Apr 6 – Apr 20 |
| Onions (sets) | Plant outdoors: Apr 6 – Apr 20 |
| Peas | Sow outdoors: Mar 23 – Apr 6 |
| Spinach | Sow outdoors: Mar 23 – Apr 6 |
| Lettuce | Sow outdoors: Apr 6 – Apr 20 |
| Carrots | Sow outdoors: Apr 6 – Apr 20 |
| Potatoes | Plant outdoors: Apr 6 – Apr 20 |
| Beans | Sow outdoors: May 11 – May 18 |
| Sweet corn | Sow outdoors: May 11 – May 18 |
| Cucumbers | Sow outdoors: May 11 – May 18 |
| Squash & zucchini | Sow outdoors: May 11 – May 18 |
| Basil | Start seeds indoors: Mar 23 – Apr 6 Transplant outdoors: May 11 – May 18 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Aug 16 (8 weeks before the average first fall frost on Oct 11).
Useful for zone 5b 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 4 | May 20 |
| First 32°F frost in fall is before | Oct 29 | Oct 11 | Sep 29 |
How to read it: in spring there is a 10% chance of a frost after May 20, so that is a safe date for tender plants. In fall there is a 10% chance of frost before September 29. A hard freeze (28°F) usually ends around April 22.
Hardiness zone by ZIP code in Marinette
- 54143 zone 5b
Nearby cities
- Suamico zone 5b, last frost May 7
- Green Bay zone 5b, last frost May 7
- Bellevue zone 5b, last frost May 6
- Howard zone 5b, last frost May 7
- Allouez zone 5b, last frost Apr 30
- Ashwaubenon zone 5b, last frost Apr 30
- De Pere zone 5b, last frost Apr 30
- Two Rivers zone 5b, last frost Apr 27
Questions
What growing zone is Marinette, WI?
Marinette is in USDA Plant Hardiness Zone 5b (average extreme winter low -15°F to -10°F), according to the USDA 2023 map.
When is the last frost in Marinette?
The average last spring frost (32°F) in Marinette is May 4. There is still a 10% chance of frost until May 20.
When can I plant tomatoes in Marinette?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around May 11 – May 18. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Marinette, WI (USC00475091), 0.6 km (0.4 mi) from the city center, elevation 180 m, based on 21 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.