When to plant spinach 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). Spinach needs 37–45 days to mature, which fits comfortably within Illinois's growing season.
When to plant spinach in Illinois: the short answer
For a spring planting, sow Mar 11 – Mar 30. Seeds germinate in soil from 35 to 75°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 spinach in Illinois, step by step
- Prepare the bed. It needs six or more hours of sun for the best growth, though four to six hours in partial shade is enough and loose soil at least 12 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 4 inches apart in rows 12 inches apart, sowing seed ½ inch deep. It tolerates hard frost, so it is one of the first crops to plant. 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: leaf miner, aphids, flea beetle. Diseases and disorders: downy mildew, white rust, damping off.
- Harvest (from about Apr 22 – Apr 30). Spinach takes 37-45 days to reach harvest. Bolts fast in heat and long days - it is really a spring and fall crop. A late-fall sowing under row cover often overwinters for an early-spring cut.
Figures come from our crop data; dates use Illinois’s average frost dates. More in the full spinach growing guide.
Spinach 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 spinach dates shift with them.
When to plant spinach in nearby states
Questions gardeners in Illinois ask
When is the best time to plant spinach in Illinois?
Sow spinach 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 spinach in the fall in Illinois?
Yes. For a fall crop, sow between August 16 and September 2, so the crop matures in cool weather before Illinois's first frost around October 14.
When will spinach planted in Illinois be ready to harvest?
Planted on time, spinach is usually ready from about April 22 to April 30, 37-45 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.