Greene County, in Illinois, sits in USDA hardiness zone 6a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Expect sweet corn, tomato, pumpkin, and apple to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Greene County holds more than one microclimate.
Soils and elevations shift across Greene County, so your frost dates and drainage aren't the county average. 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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Quick Facts
USDA Zones
6a
Last Hard Freeze (28°F)
Mar 13
County normal — light frosts run a few weeks later
First Hard Freeze (28°F)
Nov 23
County normal — light frosts arrive a few weeks earlier
County Area
348K acres
Hardiness Zone Range
Zone maps are averages across Greene County. Your yard's slope, trees, and frost pockets shift what actually grows — see your land's exact reading.
Soil in Greene County
Across Greene County, the ground is predominantly Alfisols, where Fayette, Rozetta, and Muscatune are the most extensive named soil series. The soil is generally well drained with a silt loam surface. Topsoil pH runs about 6.2–6.8, slightly acidic. Rainfall drains through hydrologic group B soils.
Soil order
Alfisols
Drainage
Well drained
Prime farmland
29%
Hydric soils
17%
Soil still varies lot by lot — soil types explained.
What Grows in Greene County
Plants matched to Greene County's USDA zones 6a — each links to its full growing profile.
Is it too late to plant in Greene County?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Feb 13; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 13 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 23 — 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.
Growing Challenges in Illinois
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 Greene County — and how to grow with it.
We checked the federal record across Greene County — 90 documented sites across 4 of the 9 source types we track.
The most significant on record: 13 brownfield sites. Former commercial or industrial land where legacy contamination may persist.
The federal record across Greene County is a modest one — a typical footprint for a growing area. Nothing here calls for alarm; it's worth knowing which recorded sites sit closest to where you grow, and each one on the map carries its type and location. If one turns out to be a near neighbor, a one-time soil test settles the question.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
Environmental Intelligence
Understanding what's nearby helps you make informed decisions about where and how to grow.
Sources Checked
across Greene County
Severity Distribution
across Greene County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Greene County, Underground Storage Tanks runs higher than the national average — 68 sites nearby. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Greene County
Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,112 plant recommendations.
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
Your Specific Parcel Matters
Greene County Average
- ●USDA Zones 6a
- ●Generic soil type for the area
- ●State-average frost dates
YOUR Parcel
- ✓Your exact hardiness zone
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Greene County
Pull a site-specific report for your exact address in Greene County, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.
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
Key Growing Facts for Greene County, Illinois
- USDA Hardiness Zones: 6a (USDA PHZM 2023)
- Last Hard Freeze (28°F): Mar 13 (county normal, NOAA 1991–2020 Climate Normals — light frosts can follow for a few weeks)
- First Hard Freeze (28°F): Nov 23 (county normal, NOAA 1991–2020 Climate Normals — light frosts can arrive a few weeks earlier)
- Days Between Hard Freezes: ~255 (county normal, NOAA 1991–2020 Climate Normals)
- County Land Area: 348K acres (US Census TIGER 2025)
Zone data: USDA ARS Plant Hardiness Zone Map 2023. Climate data: NOAA NCEI. County boundaries: US Census TIGER/Line 2025.
Frost dates here are the Greene County average. Low spots and tree cover move them by days on any one yard — see your exact frost windows.
Frequently Asked Questions
What hardiness zone is Greene County, Illinois?
Greene County sits in USDA hardiness zone 6a, per the USDA Plant Hardiness Zone Map 2023. Zones reflect average annual extreme minimum temperatures from 1991–2020 weather data.
Is it too late to plant in Greene County?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Feb 13; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 13 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 23 — 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.
When does frost risk typically end in Greene County?
The last hard freeze (28°F) in Greene County typically lands around Mar 13, per NOAA 1991–2020 climate normals — an earlier marker than the light-frost dates many planting charts quote. 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.
How long is the growing season in Greene County?
Measured between 28°F hard freezes, Greene County sees about 255 frost-free days — roughly Mar 13 through Nov 23, per 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.
What vegetables grow in Greene County?
Greene County's zone 6a supports 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.
Which hardiness zone is Greene County, really?
Officially, Greene County sits in USDA zone 6a (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.
Is the soil safe to grow vegetables in Greene County?
The federal record around Greene County shows 90 documented sites — a typical footprint for a growing area, and proximity to a documented site is information, not a diagnosis of any one yard. It's worth seeing which recorded sites sit closest to where you grow, and testing the soil before new food beds near any of them.
Just moved to Greene County — what should I know before planting?
Start with three facts. Greene County sits in USDA zone 6a, which sets what survives winter; the last 28°F hard freeze typically clears around Mar 13, with about 255 frost-free days to work with (NOAA 1991–2020 climate normals); and 90 documented sites sit on the federal record — a typical footprint for a growing area, worth a look on the contamination map before food beds. From there, matching plants to your actual soil and sun is the fun part.
Everything on this page is a Greene County 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.
Will It Grow Here?
Zone fit is the first question — each answer below reads Illinois's frost window, season length, and soil profile against the plant's real requirements.