When to plant potatoes in zone 4b
In zone 4b, where the last spring frost typically comes around May 8, sow outdoors May 2 to 9.
The zone 4b schedule for potatoes
- Sow outdoors
- May 2 to 9
- Soil warm enough (50°F), about
- May 2
- First harvest, roughly
- July 26 to September 6
From the median frost dates of the NOAA stations assigned to the 1,164 ZIP codes in zone 4b, and the timing recommended by Cooperative Extension guides for potatoes.
Dates before the last frost assume the soil has thawed and is dry enough to work: a squeezed handful crumbles instead of sticking. After a late or wet spring, wait for that even if the date has passed.
Frost risk in zone 4b
Zones are based on winter cold, not on frost dates, so the last spring frost varies a lot within a zone. Across zone 4b, the typical last frost ranges from about May 1 in the earliest tenth of ZIP codes to May 25 in the latest tenth, and the first fall frost from September 22 to October 8. For a typical place in the zone:
- April 26Risky: a later frost happens in 9 years out of 10
- May 8Typical: frost after this date in half of years
- May 22Safe: a later frost only 1 year in 10
Your dates for potatoes
Set your ZIP code at the top of the page and we will work out when to plant potatoes where you live, from the frost records of the nearest NOAA weather station. Your ZIP code is remembered on this device only.
Potatoes in zone 4b cities
| City | Typical last frost | Plant | Fall |
|---|---|---|---|
| Rochester, MN | Apr 30 | Apr 28 to May 5 | — |
| Duluth, MN | May 6 | May 19 to 26 | — |
| Lakeville, MN | May 2 | Apr 28 to May 5 | — |
| St. Cloud, MN | May 7 | May 1 to 8 | — |
| Eau Claire, WI | May 8 | Apr 28 to May 5 | — |
| Great Falls, MT | May 19 | May 12 to 19 | — |
How to grow potatoesAll zonesPotatoes in zone 4aPotatoes in zone 5aAbout zone 4b
Sources
- Potato (HGIC 1317) · Clemson Cooperative Extension, Home & Garden Information Center
- How to Grow Potatoes in Your Garden · Utah State University Extension
- Easy Gardening: Irish Potatoes (EHT-068) · Texas A&M AgriLife Extension Service
- Florida Vegetable Gardening Guide (SP 103/VH021) · UF/IFAS Extension
- Vegetable Planting Calendar for Maricopa County (AZ1005) · University of Arizona Cooperative Extension
- Solanum tuberosum · NC State Extension Gardener Plant Toolbox
- Types of Containers for Growing Vegetables · University of Maryland Extension
- Grow Potatoes in a Trash Can · UGA Cooperative Extension, DeKalb County