Root Vegetable

When to Plant Potatoes in Illinois

Incredibly satisfying to grow. There's nothing quite like digging up your own potatoes — it's like buried treasure.

The Short Answer

In Illinois, soil conditions are an important factor for potatoes. Rich prairie soils — some of the most fertile in the country. Heavy clay in many areas. Well-suited for most vegetables. Direct sow 2 weeks before your last frost date.

Illinois Frost Dates

Your planting dates depend on which part of Illinois you're in. Here are the frost date ranges by region:

Region Zones Last Frost (Spring) First Frost (Fall)
Northern Illinois (Chicago) 5a, 5b Apr 25 - May 10 Oct 1 - Oct 15
Central Illinois 5b, 6a Apr 15 - May 1 Oct 5 - Oct 20
Southern Illinois 6b, 7a Apr 1 - Apr 15 Oct 15 - Nov 1

Potatoes Planting Schedule for Illinois

Northern Illinois (Chicago) (Zones 5a, 5b)

Average last frost: Apr 25 - May 10 · Average first frost: Oct 1 - Oct 15

Direct Sow
2 wks before frost

Central Illinois (Zones 5b, 6a)

Average last frost: Apr 15 - May 1 · Average first frost: Oct 5 - Oct 20

Direct Sow
2 wks before frost

Southern Illinois (Zones 6b, 7a)

Average last frost: Apr 1 - Apr 15 · Average first frost: Oct 15 - Nov 1

Direct Sow
2 wks before frost

Growing Potatoes in Illinois

Potatoes in Illinois's Climate

Plant seed potatoes 2-3 weeks before your last frost when soil reaches 45°F. Your varied soils all grow potatoes, though clay soils produce rougher-skinned tubers than sandy loams. Hill soil around stems as they grow. Watch for late blight during humid summers — Pennsylvania and the mid-Atlantic are historically late blight territory.

Soil Considerations for Illinois

Rich prairie soils — some of the most fertile in the country. Heavy clay in many areas. Well-suited for most vegetables. Loose, well-drained soil is especially important for potatoes since the edible portion grows underground. If your soil is heavy clay, consider raised beds.

Illinois Climate & Growing Season

Continental climate with four seasons. Hot, humid summers. Cold winters. Good growing season length in central and southern regions.

Growing season length varies across Illinois: Northern Illinois (Chicago) (5a, 5b) has a last frost around Apr 25 - May 10, while Southern Illinois (6b, 7a) sees frost end around Apr 1 - Apr 15. This difference matters for potatoes — adjust your planting dates to match your specific region.

Growing Tips

Plant seed potatoes (not grocery store potatoes) 2-3 weeks before last frost. Hill soil around stems as they grow to increase yield.

Companion Planting

Plant potatoes alongside these companions for better growth:

Beans Corn Cabbage Marigolds

Keep potatoes away from:

Tomatoes Squash Sunflowers

The Bottom Line

Potatoes can be grown successfully across Illinois, but your exact planting dates depend on which region you're in. Northern Illinois (Chicago) gardeners should plan around a Apr 25 - May 10 last frost, while those in Southern Illinois can typically plant earlier. For exact dates based on your zip code, use our free planting date finder.

Related Guides

Potatoes Growing Guide National planting guide with all states Illinois Planting Calendar All plants for Illinois Potatoes in Alabama Alabama planting dates Potatoes in Alaska Alaska planting dates Potatoes in Arizona Arizona planting dates Potatoes in Arkansas Arkansas planting dates
Note: All dates are based on NOAA 30-year Climate Normals and represent historical averages, not predictions for any specific year. Always check your local weather forecast before planting frost-sensitive crops. Learn about our data sources.

Last reviewed: March 29, 2026

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