When to Plant Kale in Iowa
The toughest green in the garden. Kale laughs at frost and actually tastes sweeter after a cold snap.
The Short Answer
Iowa Frost Dates
Your planting dates depend on which part of Iowa you're in. Here are the frost date ranges by region:
| Region | Zones | Last Frost (Spring) | First Frost (Fall) |
|---|---|---|---|
| Northern Iowa | 4b, 5a | May 5 - May 20 | Sep 20 - Oct 5 |
| Central Iowa | 5a, 5b | Apr 25 - May 10 | Oct 1 - Oct 15 |
| Southern Iowa | 5b | Apr 20 - May 5 | Oct 5 - Oct 20 |
Kale Planting Schedule for Iowa
Northern Iowa (Zones 4b, 5a)
Average last frost: May 5 - May 20 · Average first frost: Sep 20 - Oct 5
Central Iowa (Zones 5a, 5b)
Average last frost: Apr 25 - May 10 · Average first frost: Oct 1 - Oct 15
Southern Iowa (Zones 5b)
Average last frost: Apr 20 - May 5 · Average first frost: Oct 5 - Oct 20
Growing Kale in Iowa
Kale in Iowa'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 Iowa
Outstanding black prairie soils. Some of the richest agricultural land in the world. Minimal amendment needed.
Iowa Climate & Growing Season
Continental climate. Cold winters, warm humid summers. Good growing season with adequate rainfall. Kale can handle frost well, which is an advantage in Iowa's climate. You can push planting dates earlier in spring and extend into fall.
Growing season length varies across Iowa: Northern Iowa (4b, 5a) has a last frost around May 5 - May 20, while Southern Iowa (5b) sees frost end around Apr 20 - May 5. 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