Kendall County, in Illinois, sits in USDA hardiness zone 5b — a zone band wide enough that plant choice, not possibility, is the interesting question.
Growers here do well with cabbage, cranberry, lavender, and collard greens — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Kendall County holds more than one microclimate.
Soils and elevations shift across Kendall County, so your frost dates and drainage aren't the county average. 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 Kendall County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Kendall County — the short answer
Kendall County, Illinois: USDA zone 5b, about 199 days between hard freezes, across 205K acres.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 10
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 26
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~199
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 205K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are county 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 Kendall County's average, not your lot's — a low corner or a tree line moves it. Against Kendall County's 199-day season, see what your own ground reads.
Heat in Kendall County
Across a year, Kendall County accumulates about 2,872 growing degree days above 50°F, about 511 fewer than the middle Illinois county — ahead of 12 of Illinois’s 102 counties. Degree days are the heat a crop actually gets to work with — more of them is more room to ripen a long-season crop before the freeze closes the window.
Grounded in PRISM Climate Group, Oregon State University — 1991–2020 monthly normals
Soil in Kendall County
Across Kendall County, the ground is predominantly Mollisols, where Drummer, Graymont, and Elpaso are the most extensive named soil series. The soil is generally moderately well drained with a silt loam surface. Topsoil pH runs about 6.2–6.7, slightly acidic. Rainfall drains through hydrologic group C soils.
Soil order
Mollisols
Drainage
Moderately well drained
Prime farmland
58%
Hydric soils
30%
Soil still varies lot by lot — soil types explained.
How the ground varies across Kendall County
The USDA soil survey maps 32% of Kendall County as moderately well drained — but another 67% drains differently: 28% poorly drained, 23% somewhat poorly drained.
Drummer is the most extensive named soil at 14% of mapped acres, then Graymont (11%) and Elpaso (5%).
Which of them your own lot sits on is a parcel question, not a county one. Check your address for the survey at your boundary.
What this means for growing in Kendall County
Each reading below is measured for Kendall County itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Drainage
MeasuredThe dominant soils across Kendall County are moderately well drained, in hydrologic group C — roughly the middle of the drainage range.
This is close to the middle most vegetables prefer: it holds enough water to carry a crop between rains without staying waterlogged. The catch is that a wet spring or a low corner can still tip it soggy.
Plant on the site as-is for most crops, but keep the lowest, slowest-draining beds for moisture-tolerant plantings.
USDA NRCS SSURGO
Surface pH
MeasuredTopsoil across Kendall County runs about pH 6.2–6.7, close to neutral.
This is the range most vegetables prefer — one correction you probably do not have to make, which is genuinely good news for a new bed.
Keep it there with compost rather than lime or sulfur, and only amend if your own soil test says otherwise.
USDA NRCS SSURGO
Wet ground
MeasuredAbout 30% of Kendall County is mapped as hydric — wetland — soil.
If your lot falls in one of those pockets, a standard in-ground bed will fight waterlogging all season, and roots that need air will struggle.
Check how your own ground drains before you dig; raised beds or moisture-loving plantings turn a wet corner from a problem into a niche.
USDA NRCS SSURGO
Season length
MeasuredKendall County runs about 199 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
The kind of country Kendall County is in
Kendall County sits in the Central Corn Belt Plains — EPA Level III, inside the wider Eastern Temperate Forests. One consistent ecological setting across the whole county.
What Grows in Kendall County
We scored all 1,086 plants against Kendall County's own USDA zone 5b and its own 199-day season between hard freezes, using the same matching engine that runs a full parcel report. These cleared both. Sun, soil pH and drainage vary lot by lot — those are the parcel questions below. Each card opens that plant's Illinois profile.
Is it too late to plant in Kendall County?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Mar 13; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 10 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 26 — long-season crops need about 90 days of runway, quick greens only 30. The tail of the season still works: sixty-day crops into late summer, quick greens after, garlic last of all.
Documented around Kendall County
Spotted lanternfly documented 21 miles from Kendall County, first recorded 2023. What to watch for.
- Japanese beetle1 documented records
- monarch butterfly2 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Kendall County
USGS estimates 128,669 lb of Glyphosate on Kendall County farmland in 2019, its largest by weight, ahead of Acetochlor (63,765 lb) and Atrazine (60,279 lb).
Farmland across the whole county, not any one lot. Check your address for the site-by-site record.
Safe to Grow Here?
What the federal record shows across Kendall County — and how to grow with it.
We checked the federal record across Kendall County — 243 documented sites across 7 of the 9 source types we track.
The most significant on record: 3 Superfund sites (none NPL-listed). Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
There's a meaningful federal record across Kendall County — worth a look before you plant food, not a reason to hold back from growing. Proximity to a documented site is information, not a diagnosis of any one yard. A soil test before new food beds is the sensible precaution here, and the map shows exactly which sites sit where, so you can see what's actually near you.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Kendall County
Closest first, across Kendall County. Listing isn't leaking, and distance isn't exposure.
- Walker's Service StationUnderground Storage Tanks · 0.9 mi
- IDOT YORKVILLEBrownfields · 1.0 mi
- Grainco FS, Inc.Underground Storage Tanks · 1.1 mi
- YORKVILLEPFAS · 1.3 mi
- Scott LeoUnderground Storage Tanks · 1.7 mi
- Township Hwy DeptUnderground Storage Tanks · 2.0 mi
- ILLINOIS TRUCK MAINTENANCEBrownfields · 2.2 mi
- Circle K #6716Underground Storage Tanks · 2.3 mi
- GROWMARK TANK & TRUCK CTRBrownfields · 2.3 mi
- Silica Sand Transport IncUnderground Storage Tanks · 2.3 mi
- Growmark IncUnderground Storage Tanks · 2.4 mi
- Kendall County Highway DeptUnderground Storage Tanks · 2.5 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Kendall County'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 Kendall County.
Total Sites
243
across Kendall County
Risk Level
Elevated
Highest-severity
3 Superfund sites (none NPL-listed)
Sources Checked
across Kendall County
Severity Distribution
across Kendall County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Kendall County, two things run higher than the national average across Kendall County — PFAS (6 sites) and Superfund (3 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.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check your specific parcel in Kendall County
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 Kendall County average
Your land is one point inside Kendall County
Everything above resolves to Kendall County as a whole — one PHZM band and one county frost record, read across 205K 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 county 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 county average.
Your Lot vs the Kendall County Average
Kendall County Average
- ●USDA Zones 5b, averaged across Kendall County
- ●One soil character for all of Kendall County
- ●Frost dates read at Kendall County's scale: Apr 10 to Oct 26
YOUR Parcel
- ✓Your exact zone, not Kendall County's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Kendall County
Pull a site-specific report for your exact address in Kendall County, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Kendall County averages can't show:
We read public map data around Kendall County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Kendall County average
How we know this about Kendall County
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at county grain; hard-freeze dates from NOAA 1991–2020 28°F normals at this county’s own record where one resolves, and the labelled statewide window where none does; soils from the USDA NRCS SSURGO survey, area-weighted across the county’s own map units; boundaries and acreage from US Census TIGER/Line 2025; the contamination and pesticide records from the federal sources named in their beats above. Where Kendall County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Kendall County
When does frost risk typically end in Kendall County?
The last hard freeze (28°F) in Kendall County typically lands around Apr 10, 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 1.
How long is the growing season in Kendall County?
Measured between 28°F hard freezes, Kendall County sees about 199 frost-free days — roughly Apr 10 through Oct 26, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 1 to Oct 12, about 164 days.
Is the soil safe to grow vegetables in Kendall County?
The federal record around Kendall County is a meaningful one — 243 documented sites, mostly Underground Storage Tanks entries (120), the nearest Underground Storage Tanks 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.
Everything above is measured at Kendall County's scale — its 5b band and its 199-day season. Your yard writes its own version of Kendall County's numbers: 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.
What this page reads at Kendall County’s own scale
9 of the readings below were taken at Kendall County's own scale — its own ~199-day span between 28°F freezes, the 3 most extensive soil series mapped here and 243 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Kendall County's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Kendall County's own 28°F hard-freeze dates and its ~199-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Kendall CountyUSDA NRCS SSURGO
- 243 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Underground Storage Tanks record about 0.9 miles outFederal environmental registers
- Kendall County's boundary and the 204,955 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~199-day seasonGrowable Ground crop-matching engine
- Kendall County sitting wholly inside the Central Corn Belt PlainsUS EPA Level III Ecoregions
- Open occurrence records documented in Kendall County for 2 tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Kendall County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every Illinois grower plans around — written at state scale, so they stay on the state guidefrom Illinois
What this page can’t tell you
- How the season shifts across Kendall County — the ~199 days above is one reading at its centre; the 12 towns below each carry their owntowns in this county →
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Kendall County's 204,955 acreswhy one lot differs from the next →
- Which of those 243 documented sites actually reaches your soil — that needs your address, the wind, and the groundwater directionhow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — none of it survives being averaged over Kendall Countyread your own land →