Caledonia, Illinois, sits in USDA hardiness zone 5b — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
Crops well matched to these conditions include cabbage, cranberry, lavender, and collard greens — though what thrives on any one site still turns on its specific soil, sun, and drainage.
Even in Caledonia, 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 Caledonia 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 Caledonia — soil, climate, flood, and parcel records. How we handle your address.
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Caledonia — the short answer
Caledonia, Illinois: USDA zone 5b, about 191 days between hard freezes, across 662 acres of town.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 15
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 23
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~191
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 662 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 Caledonia's average, not your lot's — a low corner or a tree line moves it. Against Caledonia's 191-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Caledonia
Each reading below is measured for Caledonia itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredCaledonia runs about 191 days between hard freezes — a moderate growing season.
There is room for the full run of cool-season crops plus a warm-season main crop, but the calendar is tight enough that a late spring or early fall frost still decides how much finishes.
Time warm-season transplants to your last hard freeze, and a few weeks of season extension turns a near-miss harvest into a sure one.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredCaledonia 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 Caledonia is in
Caledonia sits in the Southeastern Wisconsin Till Plains — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Caledonia's own centroid, and it is not what its county reads: Boone County is mostly Central Corn Belt Plains. The wider page above you is answering a different question about different ground.
What Grows in Caledonia
Every plant below cleared Caledonia's own zone 5b and its 191-day season. Each card opens that plant's Illinois profile. How we score.
Is it too late to plant in Caledonia?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Mar 18; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 15 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 23 — long-season crops need about 90 days of runway, quick greens only 30. As the window narrows, the plantings just get faster — fall brassicas, then greens, then garlic to finish.
What's on the federal record near Caledonia
Closest first, within ~10 miles of Caledonia. Listing isn't leaking, and distance isn't exposure.
- MCDONALD MFGBrownfields · 250 ft
- Caledonia Township Building GarageUnderground Storage Tanks · 400 ft
- Caledonia SchoolUnderground Storage Tanks · 1100 ft
- Stop-N-Go #517Underground Storage Tanks · 2.1 mi
- Poplar Grove PlantUnderground Storage Tanks · 2.2 mi
- Mathison Mobil & Coffee ShopUnderground Storage Tanks · 2.2 mi
- QUANTUM DESIGN, INCToxics Release Inventory · 2.2 mi
- Countryside MarathonUnderground Storage Tanks · 2.6 mi
- Pacemaker Countryside MarketUnderground Storage Tanks · 2.7 mi
- POPLAR GROVE AIRMOTIVEBrownfields · 3.1 mi
- HMC PRODUCTS LLCBrownfields · 3.3 mi
- SCP DISTRIBUTORS LLC (#82)Brownfields · 3.3 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Caledonia'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 Caledonia.
Sources Checked
within ~10 miles of Caledonia
Severity Distribution
within ~10 miles of Caledonia
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Caledonia, two things run higher than the national average within ~10 miles of Caledonia — PFAS (9 sites) and Toxics Release Inventory (61 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 Caledonia
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 Caledonia average
Your land is one point inside Caledonia
Everything above resolves to Caledonia as a whole — one PHZM band and one 28°F frost record, read across 662 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 Caledonia Average
Caledonia Average
- ●USDA Zones 5b, averaged across Caledonia
- ●One soil character for all of Caledonia
- ●Frost dates read at Caledonia's scale: Apr 15 to Oct 23
YOUR Parcel
- ✓Your exact zone, not Caledonia's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Caledonia
Pull a site-specific report for your exact address in Caledonia, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Caledonia averages can't show:
We read public map data around Caledonia — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Caledonia average
How we know this about Caledonia
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 Caledonia’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 Caledonia
When does frost risk typically end in Caledonia?
The last hard freeze (28°F) in Caledonia typically lands around Apr 15, 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 May 6.
When is the first frost in Caledonia?
The first hard freeze (28°F) in Caledonia typically arrives around Oct 23, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 9, so the watching starts about Sep 23 — about 191 days after the spring freeze cleared.
How long is the growing season in Caledonia?
Measured between 28°F hard freezes, Caledonia sees about 191 frost-free days — roughly Apr 15 through Oct 23, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 6 to Oct 9, about 156 days.
Is the soil safe to grow vegetables in Caledonia?
The federal record around Caledonia runs heavier than most — 730 documented sites, mostly Underground Storage Tanks entries (334), the nearest Brownfields record under a tenth of a mile out — 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.
How do I protect my plants from frost in Caledonia?
From about Sep 23 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 Oct 23 (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 Oct 23. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Caledonia's scale — its 5b band and its 191-day season. Your yard writes its own version of Caledonia'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 Caledonia’s own scale
6 of the readings below were taken at Caledonia's own scale — its own ~191-day season between 28°F freezes, the 662 acres it covers and 730 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Caledonia's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Caledonia's own 28°F hard-freeze dates, about Apr 15 and Oct 23 and the ~191-day span between themNOAA 1991–2020 Climate Normals
- 730 documented contamination sites on the federal record near Caledonia, the closest Brownfields record under a tenth of a mile out from the town centreFederal environmental registers
- Caledonia's boundary and the 662 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~191-day seasonGrowable Ground crop-matching engine
- Caledonia sits in the Southeastern Wisconsin Till Plains — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Caledonia's 662 acres read through its county's SSURGO summaryfrom Boone County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Boone 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 Boone County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Caledonia's 662 acreswhy one lot differs from the next →
- Which side of Caledonia you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 662 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields record under a tenth of a mile 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 Caledonia-wide figureread your own land →
More in Illinois
Wider growing context
What grows across IllinoisCaledonia sits outside our named growing regions, so Illinois as a whole is its closest context here.
Nearby growing guides