Planting Date FinderZone, frost date, planting window

When to plant / Illinois

When to plant sweet corn in Illinois

The planting chart is divided into Northern Illinois, Central Illinois, and Southern Illinois. Median dates for the last 32-degree freeze on the same page: Northern Illinois April 8-29; Central Illinois April 8-15; Southern Illinois April 1-8. The page also says southern Illinois can generally start crops two weeks earlier than central Illinois and northern Illinois about two weeks later; the crop rows below are the chart dates, not a recalculation of that sentence.

Source: University of Illinois Extension, When to Plant, retrieved 2026-10-10.

How this page reads that source: Illinois Fruit and Vegetable Planting Dates chart: north: May 15 to July 1; central: May 1 to July 1; south: April 15 to June 25.

North

  • May 15 to July 1 (May 15–July 1).

Central

  • May 1 to July 1 (May 1–July 1).

South

  • April 15 to June 25 (April 15–June 25).

City frost pages in Illinois are listed on Illinois.