Illinois spans USDA hardiness zones 5a-7a, with a growing season of about 190 frost-free days — a true four-season rhythm: spring greens, a full summer main crop, and a fall window that rewards planning.
The growing year is built on 34-48 inches of annual rainfall, a median of roughly 3,200 growing-degree days (base 50°F), and about 1,350 winter chill hours for tree fruit, and every crop choice answers to them. Most ground here falls among prairie loam, silt loam, clay loam, and alluvial, whose drainage habits quietly decide which beds flourish. Reliable performers under these conditions include sweet corn, tomato, pumpkin, and apple; what your own ground favors still comes down to its soil, sun, and drainage.
Grounded inUSDA PHZM 2023•NOAA Climate Normals•USDA NRCS SSURGO•GDD aggregate (Cornell CALS)•Chill-hour aggregate (MSU Extension)•EPA FRS•USDA PLANTS•Growable Ground suitability scoring
Illinois spans zones 5a-7a, but your yard sits in exactly one — and slope, tree cover, and low spots nudge it further. Enter your address and we'll score 1,112 plants against your land's actual soil, sun, and frost.
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
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Distinct growing regions within Illinois — each has its own zones, soils, and signature crops.
USDA Zones
5a-7a
USDA PHZM 2023
Last Frost
Apr 5 - May 10
NOAA 30-yr Normals
First Frost
Sep 30 - Oct 30
NOAA 30-yr Normals
Annual Rainfall
34-48 inches
NOAA Climate Normals
Zone maps are averages across Illinois. Your yard's slope, trees, and frost pockets shift what actually grows — see your land's exact reading.
The soil types that dominate Illinois — how each drains decides more about crop success than almost anything else. Tap any soil to learn what it is and how to work with it.
Drainage
Good. The crumb structure that prairie roots built lets water in and holds it like a sponge, releasing it steadily through the season.
What thrives
This is some of the most productive crop ground on Earth — corn, beans, squash, brassicas, and nearly any vegetable you plant. Prairie natives like coneflower and big bluestem are, unsurprisingly, right at home.
Drainage
Moderate. Silt holds water well and releases it steadily, though the fine particles can crust after hard rain and compact under traffic.
What thrives
The full vegetable garden does well here, and small grains, corn, and leafy greens are classic silt-loam crops. Its steady moisture suits shallow-rooted plants that dislike drought stress.
No verified open-license photo yet — this loam is close kin to the loam and silt-loam profiles above.
Drainage
Slow to moderate. Water lingers in the root zone longer than in loam, which is a gift in dry summers and a challenge in wet springs.
What thrives
Heavy feeders that appreciate steady moisture — brassicas, corn, beans, and many fruit trees. Perennials with strong root systems establish well once they are through the first season.
Drainage
Usually good: rivers sort their loads, and most alluvial soils have enough sand and silt to move water while holding plenty for roots. Low-lying pockets can run wet.
What thrives
Nearly everything — vegetables, orchards, vines, and berries all prosper on alluvium. Its depth lets roots go as far down as they care to.
Soil data: USDA NRCS SSURGO · Soil types explained
Plants well-suited to Illinois's climate, soils, and growing season — each links to its full growing profile.
Rarely: the season closes in stages, not all at once, and each stage has its crops. Across Illinois, cool-season planting typically opens about four weeks before the local last hard freeze — county medians put that freeze near Mar 17, with the middle half of counties between Mar 6 and Mar 26 (NOAA 1991–2020 climate normals). Tender transplants wait two to three weeks past it, and fall planting counts back from first freezes mostly between Nov 16 and Nov 27 — long-season crops need about 90 days of runway, quick greens only 30. With a season this long, “too late” mostly means “switch crops” — second sowings and a full fall garden are the norm, with garlic closing the year.
The plants Illinois put its name on — cultural emblems, not growing recommendations.
Violet
Viola
Designated 1907.
Quercus alba
Designated 1973. In our plant library — see its full growing profile.
GoldRush Apple
Designated 2007.
Designated 2015. In our plant library — see its full growing profile.
Plants the USDA PLANTS Database documents as native and present in Illinois — a real per-state range, not just a zone match. Presence is statewide, so a plant may still be uncommon in your specific county; your state’s Cooperative Extension or a native-plant society is the local authority.
US-native plants whose hardiness range overlaps Illinois’s USDA zones 5a-7a but which USDA PLANTS doesn’t map to a single state range here. Zone overlap is a starting filter, not a range map.
What an experienced grower plans around here — each one has a move.
Heavy clay soils in northern IL drain poorly
A raised bed solves the standing-water problem in a weekend; fall compost keeps improving the clay beneath it.
Extreme temperature swings between summer and winter
Wide swings reward truly hardy varieties and a deep mulch blanket — insulation smooths what the weather won't.
Japanese beetles are a major garden pest
Hand-pick into soapy water early and often, and skip the traps (they attract more than they catch) — extension IPM guides have the rest.
For cultivar selection, pest pressure, and planting-time guidance specific to Illinois, the University of Illinois Extension is the authoritative local source.
Safe to Grow Here?What the federal record shows across Illinois — and how to grow with it.
We checked the federal record across Illinois — 52,971 documented sites across 8 of the 9 source types we track.
The most significant on record: 622 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Illinois carries one of the heavier federal records we track — and that's not a verdict on your yard. Proximity to a documented site is information, not a diagnosis: nothing here says any particular parcel is affected. It does earn one concrete step — before food beds go in the ground, a professional soil test tells you exactly what you're working with, and raised beds with clean imported soil grow well almost anywhere in the meantime.
Severity Distribution
across Illinois
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Illinois, two things run higher than the national average — PFAS (482 sites) and Toxic Release Inventory (3,504 sites). That's not a problem with your land — it's information about it.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Toxic Release Inventory: TRI facilities report annual chemical releases to air, water, and land.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
State averages sketch the shape. Your soil, sun exposure, drainage, and microclimate decide what actually takes. Pull a site-specific report for your exact parcel.
Enter your address. We read your soil, sun, drainage, and frost dates, then score 1,112 plants against the real conditions on your land.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources analyzed in seconds
Illinois spans USDA hardiness zones 5a-7a, per the USDA Plant Hardiness Zone Map 2023. Zones reflect average annual extreme minimum temperatures from 1991–2020 weather data.
Rarely: the season closes in stages, not all at once, and each stage has its crops. Across Illinois, cool-season planting typically opens about four weeks before the local last hard freeze — county medians put that freeze near Mar 17, with the middle half of counties between Mar 6 and Mar 26 (NOAA 1991–2020 climate normals). Tender transplants wait two to three weeks past it, and fall planting counts back from first freezes mostly between Nov 16 and Nov 27 — long-season crops need about 90 days of runway, quick greens only 30. With a season this long, “too late” mostly means “switch crops” — second sowings and a full fall garden are the norm, with garlic closing the year.
Across Illinois, the middle half of counties see their last hard freeze (28°F) between about Mar 6 and Mar 26, with a county median near Mar 17 (NOAA 1991–2020 climate normals). That marks the hard freeze, not the last light frost — light frosts can still bite for a few more weeks, so tender transplants usually wait another 2–3 weeks.
Measured between 28°F hard freezes, growing seasons across Illinois's counties mostly run about 235 to 266 days, with a county median near 249 (NOAA 1991–2020 climate normals). Tender crops get a somewhat shorter practical window, since lighter frosts reach a few weeks past the hard-freeze dates on both ends.
Illinois's zones 5a-7a support a wide range — strong performers include Sweet Corn, Tomato, Pumpkin, Apple, and Coneflower. What actually takes on any one site comes down to its soil, sun, and drainage, and we score each plant against the real conditions at your address.
Officially, Illinois spans USDA zones 5a-7a (USDA PHZM 2023) — but a zone is a 30-year average of winter's coldest night across an area, and it can't see any one yard. A south-facing slope, a tree line, or a low frost pocket can shift a single site by half a zone either way, which is why neighboring gardeners often quote different numbers. We read the conditions at your exact address — soil, sun, slope, and frost — and score 1,112 plants against what's actually there.
The federal record across Illinois runs heavier than most — 52,971 documented sites — so test the soil before planting food in the ground, and raised beds with clean imported soil grow well in the meantime. Even here, proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what's recorded and where.
Start with three facts. Illinois spans USDA zones 5a-7a, which sets what survives winter; last hard freezes range from about Mar 6 to Mar 26 across its counties (NOAA 1991–2020 climate normals); and 52,971 documented sites sit on the federal record here, so a soil test before food beds is the smart first step. From there, matching plants to your actual soil and sun is the fun part.
Everything on this page is a Illinois average. Your yard writes its own version — we read soil, sun, drainage, and frost at your exact address. Try it for 14 days — no card required.
Explore growing conditions by county — each has its own zone range and land area.
Explore growing conditions by city or town in Illinois.
