When to Plant Vegetables in Illinois

Last updated September 6, 2026

Last spring frost (median)

Apr 16

First fall frost (median)

Oct 21

Growing season

~188 days

Across Illinois, the median last frost falls around Apr 16 and the median first fall frost around Oct 21, from NOAA's 1991-2020 climate normals for the weather station nearest each of the state's ZIP codes. Half of years have a later last frost; 1 year in 10 is later than about May 3. Every date in the table below is calculated directly from those two dates using standard, extension-verified planting-offset rules, and the ZIP box recalculates it for your own station.

Illinois Planting Calendar

Crop	Method	Spring window	Fall window
Tomatoes (Frost-sensitive)	Start Indoors	Start indoors: Feb 19 - Mar 5 Transplant outdoors: Apr 23 - Apr 30 Transplant once nighttime lows are reliably above 50°F, not just after the calendar frost date.	None
Peppers (Frost-sensitive)	Start Indoors	Start indoors: Feb 5 - Feb 19 Transplant outdoors: Apr 30 and later Peppers want warmer soil than tomatoes -- when in doubt, wait the extra week.	None
Cucumbers (Frost-sensitive)	Direct SowTransplant	Apr 23 - Apr 30 The real trigger is soil temperature (70°F+ at 1 inch deep), not the calendar -- this window is a practical estimate of when that soil temperature typically arrives after the last frost.	None
Beans (Frost-sensitive)	Direct Sow	Apr 16 - Apr 23 Bean seed rots in cold, wet soil -- wait until the soil has warmed to at least 60°F.	None
Lettuce (Frost-tolerant)	Direct Sow	Mar 19 - Apr 2 Cold-tolerant -- a good candidate for succession sowing every 2-3 weeks through spring.	Sow by Aug 18 - Aug 28
Carrots (Frost-tolerant)	Direct Sow	Mar 12 - Apr 2	None
Squash / zucchini (Frost-sensitive)	Direct SowTransplant	Apr 16 - Apr 23 Squash doesn’t tolerate cold -- wait for soil to reach about 70°F.	None
Broccoli (Frost-tolerant)	Start Indoors	Feb 19 - Mar 5	Sow by Jul 19 - Jul 29
Spinach (Frost-tolerant)	Direct Sow	Mar 5 - Mar 19 Sow as soon as the soil can be worked -- extension sources cite anywhere from 2-8 weeks before last frost depending on region; this is a middle estimate.	Sow by Aug 8 - Aug 18
Peas (Frost-tolerant)	Direct Sow	Mar 5 - Mar 19 Cold-tolerant -- sow as soon as the soil can be worked.	None
Onions (sets or transplants) (Frost-tolerant)	Transplant	Mar 19 - Apr 2 This window is for long-day onion varieties, the standard choice across most of the US. Gardeners in the Deep South growing short-day varieties follow a different fall/winter planting schedule.	None
Radishes (Frost-tolerant)	Direct Sow	Mar 5 - Mar 19 Fast-maturing -- a reliable succession crop every 1-2 weeks through spring.	None
Corn (Frost-sensitive)	Direct Sow	Apr 16 - Apr 23 Needs soil temperature of at least 50°F to germinate, with 65-75°F optimal for even germination.	None
Pumpkins (Frost-sensitive)	Direct Sow	Apr 16 - Apr 23 Soil should reach about 65-70°F. If timing for a fall harvest target, count backward from your target date using the variety’s days-to-maturity instead of using this spring window.	None
Beets (Frost-tolerant)	Direct Sow	Mar 19 - Apr 2	None
Cabbage (Frost-tolerant)	Start Indoors	Feb 19 - Mar 5	None
Cauliflower (Frost-tolerant)	Start Indoors	Feb 19 - Mar 5 Extension sources vary more on this crop than most (some cite as few as 4 weeks, others up to 10) -- this range is a defensible middle estimate, usually grown on the same schedule as cabbage.	None
Kale (Frost-tolerant)	Direct Sow	Mar 5 - Mar 19	Sow by Aug 18 - Aug 28
Basil (Frost-sensitive)	Start Indoors	Start indoors: Feb 19 - Mar 5 Transplant outdoors: Apr 30 and later Frost-sensitive, unlike the cold-tolerant crops above -- transplant only after ALL frost risk has passed and soil has warmed to 60°F or more.	None

Summer vegetable beds full of tomatoes, sweet corn, beans and squash in a backyard garden in the Illinois prairie, with flat farmland, oaks and a red barn in the distance — The same kind of garden in summer: tomatoes, sweet corn, beans and squash. AI-generated image.

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The Spacing & Planting Cheat Sheet

When to start, when to plant, how far apart.

Understanding Your Planting Windows

These windows come from a simple, real calculation: take Illinois's median last-frost and first-frost dates, then apply fixed, extension-verified offset rules for each crop (for example, "start tomato seeds indoors 6-8 weeks before your last frost"). Because the offset rules are the same nationwide but Illinois's actual frost dates are specific to Illinois, the resulting dates are genuinely Illinois's own, not a generic template.

These are statewide medians, though, and your own yard may run warmer or colder depending on elevation, urban heat, or microclimate. Enter your ZIP code in the box at the top of the page for your nearest station's dates. For Illinois's full zone range from coldest to warmest areas, see the Illinois Growing Zone page.

Want exact seed-starting dates for your specific ZIP code, not just the state average? Use the Seed Starting Calculator.

Sources & further reading

Frost dates come from NOAA NCEI's U.S. Climate Normals, 1991-2020: for each of Illinois's ZIP codes, the median last and first 32°F dates at the nearest weather station (an airport station within 15 miles where there is one), with ZIP code points from the U.S. Census Bureau's 2023 ZCTA Gazetteer. The same station data drives our Frost Date Calculator. Planting-offset rules are drawn from US Cooperative Extension sources including UGA, UMN, NC State, Utah State, Iowa State, Penn State, and UConn Extension, cited crop-by-crop in the table above. For more on how we build and verify reference data across this site, see our methodology page.

Planting calendars for nearby states

Frost dates shift gradually across state lines, not sharply:

Or browse all 51 state planting calendars.