When to Plant Kale in Wisconsin
The toughest green in the garden. Kale laughs at frost and actually tastes sweeter after a cold snap.
The Short Answer
Wisconsin Frost Dates
Your planting dates depend on which part of Wisconsin you're in. Here are the frost date ranges by region:
| Region | Zones | Last Frost (Spring) | First Frost (Fall) |
|---|---|---|---|
| Northern Wisconsin | 3b, 4a | May 15 - Jun 1 | Sep 10 - Sep 25 |
| Central Wisconsin | 4a, 4b | May 5 - May 20 | Sep 20 - Oct 5 |
| Southern Wisconsin | 4b, 5a, 5b | Apr 25 - May 10 | Oct 1 - Oct 15 |
Kale Planting Schedule for Wisconsin
Northern Wisconsin (Zones 3b, 4a)
Average last frost: May 15 - Jun 1 · Average first frost: Sep 10 - Sep 25
Central Wisconsin (Zones 4a, 4b)
Average last frost: May 5 - May 20 · Average first frost: Sep 20 - Oct 5
Southern Wisconsin (Zones 4b, 5a, 5b)
Average last frost: Apr 25 - May 10 · Average first frost: Oct 1 - Oct 15
Growing Kale in Wisconsin
Kale in Wisconsin's Climate
Kale is your climate's superstar. It thrives in cool weather, survives hard frosts, and actually improves in flavor after cold exposure. In northern zones, kale produces from April through December — one of the longest harvests of any crop. Snow-covered kale harvested in December is genuinely sweeter than summer kale. If you grow nothing else in a cold climate, grow kale.
Soil Considerations for Wisconsin
Rich agricultural soils in southern half. Sandy soils in central plain. Heavy clay in some lake regions. Generally fertile.
Wisconsin Climate & Growing Season
Cold winters. Warm summers. Lake Michigan moderates eastern climate. Good growing season in south. Short season in north. Kale can handle frost well, which is an advantage in Wisconsin's climate. You can push planting dates earlier in spring and extend into fall.
Growing season length varies across Wisconsin: Northern Wisconsin (3b, 4a) has a last frost around May 15 - Jun 1, while Southern Wisconsin (4b, 5a, 5b) sees frost end around Apr 25 - May 10. This difference matters for kale — adjust your planting dates to match your specific region.
Growing Tips
Harvest outer leaves first, leaving the center to keep growing. Can survive temperatures down to 10°F with mulch protection.
Companion Planting
Plant kale alongside these companions for better growth:
Keep kale away from:
The Bottom Line
Last reviewed: March 29, 2026