When to plant peas in Illinois
Illinois’s average last spring frost is April 20, and the first fall frost typically arrives around October 14 — about 177 frost-free days (USDA zones 5a, 5b, 6a, 6b, 7a). Pea needs 55–70 days to mature, which fits comfortably within Illinois's growing season.
When to plant peas in Illinois: the short answer
For a spring planting, sow Mar 11 – Mar 30. Seeds germinate in soil from 40 to 85°F.
Succession sow again in Illinois: Mar 28 · Apr 9 · Apr 21 · May 3 · May 15
Spring succession stops before summer heat makes it bolt. Start sowing again in late summer for a fall crop (see the fall window above).
Windows are ~1–2 week bands around each date. Frost dates are a statewide average from NOAA/NCEI normals; your town may differ by two weeks or more. Calendar year 2026.
How to grow peas in Illinois, step by step
- Prepare the bed. They need at least six to eight hours of direct sun a day and loose soil at least 18 inches deep, with a pH between 6.0 and 7.5. Dig in compost before planting.
- Sow outdoors (Mar 11 – Mar 30). Space plants about 2 inches apart in rows 18 inches apart, sowing seed 1 inch deep. It handles frost well, so it can go out before the last frost date. As a cool-season crop it does best before summer heat arrives in Illinois.
- Water and feed. Give it steady, even moisture, about an inch of water a week from rain or the hose.
- Watch for pests and problems. Pests: aphids, pea weevil, armyworm. Diseases and disorders: powdery mildew, fusarium wilt, root rot.
- Harvest (from about May 10 – May 25). Pea takes 55-70 days to reach harvest. Sow as soon as the soil can be worked - 4 to 6 weeks before the last frost. Production stops once daytime highs stay above ~80 F.
Figures come from our crop data; dates use Illinois’s average frost dates. More in the full pea growing guide.
Pea planting dates by USDA zone in Illinois
Illinois spans USDA zones 5a, 5b, 6a, 6b, 7a. Colder zones, usually higher or further inland, have a later last spring frost and an earlier first fall frost than the state average, so the pea dates shift with them.
When to plant peas in nearby states
Questions gardeners in Illinois ask
When is the best time to plant peas in Illinois?
Sow peas in Illinois between March 11 and March 30. That timing is set by Illinois's average last spring frost of April 20.
Can I plant peas in the fall in Illinois?
Yes. For a fall crop, sow between July 26 and August 12, so the crop matures in cool weather before Illinois's first frost around October 14.
When will peas planted in Illinois be ready to harvest?
Planted on time, peas are usually ready from about May 10 to May 25, 55-70 days after sowing.
When is the last frost in Illinois?
On average around April 20, with the first fall frost around October 14 - about 177 frost-free days. Your town may differ by two weeks or more.