Carbon Hill, Illinois, sits in USDA hardiness zone 5b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Crops well matched to these conditions include cabbage, blueberry, lavender, and collard greens — though what thrives on any one site still turns on its specific soil, sun, and drainage.
Even in Carbon Hill, no two yards are alike.
A low spot, a south-facing slope, or a stand of trees moves the frost date and sun across a single Carbon Hill lot. Enter your address and we'll score 1,086 plants against your land's actual soil, sun, and frost.
We read public map data around Carbon Hill — soil, climate, flood, and parcel records. How we handle your address.
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Carbon Hill — the short answer
Carbon Hill, Illinois: USDA zone 5b, about 206 days between hard freezes, across 116 acres of town.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 9
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 1
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~206
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 116 acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are this town’s own 28°F normals: light frosts run a few weeks past them, and tender transplants usually wait 2–3 weeks after the last hard freeze.
Hardiness Zone Range
Zone 5b is Carbon Hill's average, not your lot's — a low corner or a tree line moves it. Against Carbon Hill's 206-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Carbon Hill
Each reading below is measured for Carbon Hill itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredCarbon Hill runs about 206 days between hard freezes — a long growing season.
There is slack for succession plantings and slow-finishing crops: many vegetables can be sown twice, and the heat-lovers have time to ripen fully.
Plan a second sowing of quick crops after the first comes out, and use the fall window most gardeners let sit idle.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredCarbon Hill sits in USDA hardiness zone 5b.
The zone sets which perennials, shrubs, and fruit trees live through an average winter here — a plant rated for a colder zone is a safe bet, one rated warmer needs winter protection or gets treated as an annual.
Match perennials and fruit to the zone before you buy, so nothing you plant is a gamble against the cold.
USDA PHZM 2023
The kind of country Carbon Hill is in
Carbon Hill sits in the Central Corn Belt Plains — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Carbon Hill's own centroid rather than borrowed from Grundy County.
What Grows in Carbon Hill
Every plant below cleared Carbon Hill's own zone 5b and its 206-day season. Each card opens that plant's Illinois profile. How we score.
Is it too late to plant in Carbon Hill?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Mar 12; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 9 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 1 — long-season crops need about 90 days of runway, quick greens only 30. Here the season winds down slowly: late sowings, a real autumn harvest, and garlic in the ground before the first hard freeze.
What's on the federal record near Carbon Hill
Closest first, within ~10 miles of Carbon Hill. Listing isn't leaking, and distance isn't exposure.
- COAL CITYPFAS · 0.9 mi
- Coal City Shell #1813Underground Storage Tanks · 1.0 mi
- Commercial Bldg Aka Broadwy FordUnderground Storage Tanks · 1.0 mi
- Coal City Minit Mart #619Underground Storage Tanks · 1.0 mi
- Diamond GasUnderground Storage Tanks · 1.0 mi
- Super Pantry 41Underground Storage Tanks · 1.0 mi
- Trotter InsuranceUnderground Storage Tanks · 1.1 mi
- Bill's Pit StopUnderground Storage Tanks · 1.1 mi
- CVS PHARMACY 10599Brownfields · 1.1 mi
- BLACHFORD CORPORATIONToxics Release Inventory · 1.3 mi
- Grundy County Redi-MixUnderground Storage Tanks · 1.3 mi
- QUALITY AUTO BODYBrownfields · 1.4 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Carbon Hill's center, not your beds. Run your own address for what's upwind of you specifically.
Environmental Intelligence
The counts behind that headline — every source type on the record near Carbon Hill.
Sources Checked
within ~10 miles of Carbon Hill
Severity Distribution
within ~10 miles of Carbon Hill
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Carbon Hill, two things run higher than the national average within ~10 miles of Carbon Hill — PFAS (5 sites) and Toxics Release Inventory (26 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.
Toxics 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.
Check your specific parcel in Carbon Hill
Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,086 plant recommendations.
25+ data sources read at your address, not the Carbon Hill average
Your land is one point inside Carbon Hill
Everything above resolves to Carbon Hill as a whole — one PHZM band and one 28°F frost record, read across 116 acres. Your parcel is one point inside that footprint. Slope, tree cover, a low spot that pools cold air, and what is in the soil are all resolved at the address, and none of them are visible at town scale. That is the honest boundary of this page, and the reason the next step is a reading of your own ground rather than a better local average.
Your Lot vs the Carbon Hill Average
Carbon Hill Average
- ●USDA Zones 5b, averaged across Carbon Hill
- ●One soil character for all of Carbon Hill
- ●Frost dates read at Carbon Hill's scale: Apr 9 to Nov 1
YOUR Parcel
- ✓Your exact zone, not Carbon Hill's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Carbon Hill
Pull a site-specific report for your exact address in Carbon Hill, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Carbon Hill averages can't show:
We read public map data around Carbon Hill — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Carbon Hill average
How we know this about Carbon Hill
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this town’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Carbon Hill’s own record; boundaries and acreage from US Census TIGER/Line 2025; the contamination records from the federal sources named in their beats above. Soil is not read at town grain anywhere on this page — there is no town-resolution survey in our data, which is why you will find no soil grid here rather than a statewide one wearing a local label. The resolution ledger below names every figure this page inherited.
Common questions about Carbon Hill
When does frost risk typically end in Carbon Hill?
The last hard freeze (28°F) in Carbon Hill typically lands around Apr 9, per NOAA 1991–2020 climate normals — earlier than the light-frost dates most charts quote. That marks the hard freeze, not the last light frost — lighter frosts keep biting past it, which is why tender transplants here wait until about Apr 30.
When is the first frost in Carbon Hill?
The first hard freeze (28°F) in Carbon Hill typically arrives around Nov 1, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 18, so the watching starts about Oct 2 — about 206 days after the spring freeze cleared.
How long is the growing season in Carbon Hill?
Measured between 28°F hard freezes, Carbon Hill sees about 206 frost-free days — roughly Apr 9 through Nov 1, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 30 to Oct 18, about 171 days.
Is the soil safe to grow vegetables in Carbon Hill?
The federal record around Carbon Hill is a meaningful one — 329 documented sites, mostly Underground Storage Tanks entries (169), the nearest PFAS record about 0.9 miles out — so a soil test before new food beds is a sensible precaution here, not a reason to hold back from growing. Remember that proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what sits where.
How do I protect my plants from frost in Carbon Hill?
From about Oct 2 the job here turns from planting to protecting — the last start even a 30-day crop can finish. As the season closes around the first 28°F hard freeze near Nov 1 (NOAA 1991–2020 climate normals), three moves buy time: row cover or an old sheet over tender plants on still, clear nights; water the soil the afternoon before a freeze, so it holds warmth overnight; and harvest tomatoes, peppers and basil before Nov 1. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Carbon Hill's scale — its 5b band and its 206-day season. Your yard writes its own version of Carbon Hill's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
What this page reads at Carbon Hill’s own scale
6 of the readings below were taken at Carbon Hill's own scale — its own ~206-day season between 28°F freezes, the 116 acres it covers and 329 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Carbon Hill's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Carbon Hill's own 28°F hard-freeze dates, about Apr 9 and Nov 1 and the ~206-day span between themNOAA 1991–2020 Climate Normals
- 329 documented contamination sites on the federal record near Carbon Hill, the closest PFAS record about 0.9 miles out from the town centreFederal environmental registers
- Carbon Hill's boundary and the 116 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~206-day seasonGrowable Ground crop-matching engine
- The ecoregion at Carbon Hill's own centroid, the Central Corn Belt PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Carbon Hill's 116 acres read through its county's SSURGO summaryfrom Grundy County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Grundy County
- The growing challenges every Illinois grower plans around — written at state scale, so they stay on the state guidefrom Illinois
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Grundy County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Carbon Hill's 116 acreswhy one lot differs from the next →
- Which side of Carbon Hill you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 116 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest PFAS record about 0.9 miles out, measured from the town centrehow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — measured at your address, and averaged away by any Carbon Hill-wide figureread your own land →
More in Illinois
Wider growing context
What grows across IllinoisCarbon Hill sits outside our named growing regions, so Illinois as a whole is its closest context here.
Nearby growing guides