DuPage County, in Illinois, sits in USDA hardiness zone 5b — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
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.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
DuPage County holds more than one microclimate.
Soils and elevations shift across DuPage 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 DuPage County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
DuPage County — the short answer
DuPage County, Illinois: USDA zone 5b, about 200 days between hard freezes, across 210K 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 27
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~200
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 210K 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 DuPage County's average, not your lot's — a low corner or a tree line moves it. Against DuPage County's 200-day season, see what your own ground reads.
Heat in DuPage County
Across a year, DuPage County accumulates about 2,900 growing degree days above 50°F, about 483 fewer than the middle Illinois county — ahead of 13 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 DuPage County
Across DuPage County, the ground is predominantly Mollisols, where Markham, Ashkum, and Ozaukee are the most extensive named soil series. The soil is generally moderately well drained with a silt loam surface. Topsoil pH runs about 6.2–6.8, slightly acidic. Rainfall drains through hydrologic group C/D soils.
Soil order
Mollisols
Drainage
Moderately well drained
Prime farmland
39%
Hydric soils
27%
Soil still varies lot by lot — soil types explained.
How the ground varies across DuPage County
The USDA soil survey maps 57% of DuPage County as moderately well drained — but another 41% drains differently: 18% poorly drained, 13% somewhat poorly drained.
Markham is the most extensive named soil at 17% of mapped acres, then Ashkum (12%) and Ozaukee (10%).
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 DuPage County
Each reading below is measured for DuPage 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 DuPage County are moderately well drained, in hydrologic group C/D — 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 DuPage County runs about pH 6.2–6.8, 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 27% of DuPage 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
MeasuredDuPage County runs about 200 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
The kind of country DuPage County is in
DuPage 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 DuPage County
We scored all 1,086 plants against DuPage County's own USDA zone 5b and its own 200-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 DuPage County?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. 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 27 — 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.
Documented around DuPage County
Spotted lanternfly documented 4 miles from DuPage County, first recorded 2023. What to watch for.
- Japanese beetle19 documented records
- monarch butterfly1,774 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in DuPage County
USGS estimates 2,337 lb of Glyphosate on DuPage County farmland in 2019, its largest by weight, ahead of Acetochlor (1,554 lb) and Atrazine (1,519 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 DuPage County — and how to grow with it.
We checked the federal record across DuPage County — 3,490 documented sites across 6 of the 9 source types we track.
The most significant on record: 24 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
DuPage County 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.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near DuPage County
Closest first, across DuPage County. Listing isn't leaking, and distance isn't exposure.
- Wheaton AMC/Jeep/RenaultUnderground Storage Tanks · 2500 ft
- City of WheatonUnderground Storage Tanks · 2600 ft
- Dons AutoUnderground Storage Tanks · 0.5 mi
- Suburban Buick CoUnderground Storage Tanks · 0.5 mi
- Wilson Ave Pumping StationUnderground Storage Tanks · 0.5 mi
- Packey Webb FordUnderground Storage Tanks · 0.5 mi
- Bucky's Express #540Underground Storage Tanks · 0.6 mi
- Wheaton 66Underground Storage Tanks · 0.6 mi
- Amoco SS #9828 Facility #11904Underground Storage Tanks · 0.6 mi
- CitgoUnderground Storage Tanks · 0.6 mi
- GLEN ELLYN DODGE INCBrownfields · 0.6 mi
- Glen Ellyn Renu Service CenterUnderground Storage Tanks · 0.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from DuPage 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 DuPage County.
Sources Checked
across DuPage County
Severity Distribution
across DuPage County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around DuPage County, two things run higher than the national average across DuPage County — Toxics Release Inventory (294 sites) and PFAS (32 sites). That's not a problem with your land — it's information about it.
Toxics Release Inventory: TRI facilities report annual chemical releases to air, water, and land.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Check your specific parcel in DuPage 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 DuPage County average
Your land is one point inside DuPage County
Everything above resolves to DuPage County as a whole — one PHZM band and one county frost record, read across 210K 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 DuPage County Average
DuPage County Average
- ●USDA Zones 5b, averaged across DuPage County
- ●One soil character for all of DuPage County
- ●Frost dates read at DuPage County's scale: Apr 10 to Oct 27
YOUR Parcel
- ✓Your exact zone, not DuPage County's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in DuPage County
Pull a site-specific report for your exact address in DuPage County, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that DuPage County averages can't show:
We read public map data around DuPage County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the DuPage County average
How we know this about DuPage 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 DuPage County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about DuPage County
When does frost risk typically end in DuPage County?
The last hard freeze (28°F) in DuPage 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 DuPage County?
Measured between 28°F hard freezes, DuPage County sees about 200 frost-free days — roughly Apr 10 through Oct 27, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 1 to Oct 13, about 165 days.
Is the soil safe to grow vegetables in DuPage County?
The federal record around DuPage County runs heavier than most — 3,490 documented sites, mostly Underground Storage Tanks entries (1,561), the nearest Underground Storage Tanks record about 0.5 miles 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.
Everything above is measured at DuPage County's scale — its 5b band and its 200-day season. Your yard writes its own version of DuPage 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 DuPage County’s own scale
9 of the readings below were taken at DuPage County's own scale — its own ~200-day span between 28°F freezes, the 3 most extensive soil series mapped here and 3,490 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- DuPage County's own USDA hardiness band, zones 5bUSDA PHZM 2023
- DuPage County's own 28°F hard-freeze dates and its ~200-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in DuPage CountyUSDA NRCS SSURGO
- 3,490 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Underground Storage Tanks record about 0.5 miles outFederal environmental registers
- DuPage County's boundary and the 209,851 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~200-day seasonGrowable Ground crop-matching engine
- DuPage County sitting wholly inside the Central Corn Belt PlainsUS EPA Level III Ecoregions
- Open occurrence records documented in DuPage County for 2 tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto DuPage 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 DuPage County — the ~200 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 DuPage County's 209,851 acreswhy one lot differs from the next →
- Which of those 3,490 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 DuPage Countyread your own land →