When to Plant Sweet Potatoes in Iowa
Not related to regular potatoes at all. Sweet potatoes need heat and a long growing season but reward with incredible harvests.
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 |
Sweet Potatoes 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 Sweet Potatoes in Iowa
Sweet Potatoes in Iowa's Climate
Sweet potatoes are a stretch in cold climates — the crop needs 90+ days of warm soil and air. Southern zones 5b-5a gardeners can succeed with Beauregard (90 days), black plastic mulch, and raised beds. Northern zone 3-4 gardeners should skip sweet potatoes — the season simply isn't long enough. Container growing on a sun-baked patio sometimes works where in-ground doesn't.
Soil Considerations for Iowa
Outstanding black prairie soils. Some of the richest agricultural land in the world. Minimal amendment needed. Loose, well-drained soil is especially important for sweet potatoes since the edible portion grows underground. If your soil is heavy clay, consider raised beds.
Iowa Climate & Growing Season
Continental climate. Cold winters, warm humid summers. Good growing season with adequate rainfall. Sweet Potatoes cannot tolerate any frost, so wait until all frost danger has passed before transplanting outside. Watch local forecasts carefully in spring.
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 sweet potatoes — transplant timing shifts by several weeks across the state.
Growing Tips
Grow from slips, not seeds. Start slips from a sweet potato in water 8 weeks before transplanting. Cure harvested tubers in warmth for 10 days.
Companion Planting
Plant sweet potatoes alongside these companions for better growth:
Keep sweet potatoes away from:
The Bottom Line
Last reviewed: March 29, 2026