Whiteside County, in Illinois, sits in USDA hardiness zone 5b — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
A short list that earns its place here — cabbage, cranberry, lavender, and collard greens — with any one site's soil, sun, and drainage making the final cut.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Whiteside County holds more than one microclimate.
Soils and elevations shift across Whiteside 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 Whiteside County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Whiteside County — the short answer
Whiteside County, Illinois: USDA zone 5b, about 194 days between hard freezes, across 438K acres.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 11
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 22
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~194
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 438K 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 Whiteside County's average, not your lot's — a low corner or a tree line moves it. Against Whiteside County's 194-day season, see what your own ground reads.
Heat in Whiteside County
Across a year, Whiteside County accumulates about 2,867 growing degree days above 50°F, about 516 fewer than the middle Illinois county — ahead of 11 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 Whiteside County
Across Whiteside County, the ground is predominantly Mollisols, where Seaton, Dickinson, and Greenbush are the most extensive named soil series. The soil is generally well drained with a silt loam surface. Topsoil pH runs about 6.4–6.7, slightly acidic. Rainfall drains through hydrologic group B soils.
Soil order
Mollisols
Drainage
Well drained
Prime farmland
38%
Hydric soils
26%
Soil still varies lot by lot — soil types explained.
How the ground varies across Whiteside County
The USDA soil survey maps 54% of Whiteside County as well drained — but another 44% drains differently: 24% poorly drained, 12% somewhat poorly drained.
Seaton is the most extensive named soil at 9% of mapped acres, then Dickinson (5%) and Greenbush (4%).
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 Whiteside County
Each reading below is measured for Whiteside 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 Whiteside County are well drained, in hydrologic group B — ground that drains quickly.
The upside is soil you can work early in spring and roots that never drown; the cost is that fast-draining ground dries out fast and leaches nutrients away before plants can use them.
Work in compost and mulch to hold moisture and feed, and water more often in short doses than deep and rarely.
USDA NRCS SSURGO
Surface pH
MeasuredTopsoil across Whiteside County runs about pH 6.4–6.7, 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 26% of Whiteside 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
MeasuredWhiteside County runs about 194 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 Whiteside County is in
Whiteside County spans 2 EPA Level III ecoregions — Central Corn Belt Plains (85%) and Interior River Valleys and Hills (15%). Which one your land falls in changes what grows wild there and how the ground behaves, and a county-wide answer cannot tell you which.
What Grows in Whiteside County
We scored all 1,086 plants against Whiteside County's own USDA zone 5b and its own 194-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 Whiteside 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 14; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 11 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 22 — long-season crops need about 90 days of runway, quick greens only 30. Even past midsummer there is room for a true fall garden here, and garlic planted near the close carries the momentum into next year.
Documented around Whiteside County
- monarch butterfly662 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Whiteside County
USGS estimates 312,761 lb of Glyphosate on Whiteside County farmland in 2019, its largest by weight, ahead of Atrazine (130,462 lb) and Metolachlor & Metolachlor-s (119,494 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 Whiteside County — and how to grow with it.
We checked the federal record across Whiteside County — 422 documented sites across 7 of the 9 source types we track.
The most significant on record: 6 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 Whiteside 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 Whiteside County
Closest first, across Whiteside County. Listing isn't leaking, and distance isn't exposure.
- Whiteside Fs Inc PetroUnderground Storage Tanks · 1.3 mi
- ROCK RIVER FABRICATIONSBrownfields · 2.0 mi
- ROCK RIVER FABRICATIONSToxics Release Inventory · 2.0 mi
- Gold Star FS Lyndon Bulk PlantUnderground Storage Tanks · 2.1 mi
- Lydon Township GarageUnderground Storage Tanks · 2.3 mi
- Gibson Oil Co.Underground Storage Tanks · 2.4 mi
- Gte NorthUnderground Storage Tanks · 2.5 mi
- Lyndon StoreUnderground Storage Tanks · 2.6 mi
- ERI-LYN FARMS, INCCAFO · 3.0 mi
- Whiteside County Highway DeptUnderground Storage Tanks · 3.2 mi
- Quality Ready Mix Concrete Co., Inc.Underground Storage Tanks · 3.3 mi
- Wiersema Charter Ser IncUnderground Storage Tanks · 3.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Whiteside 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 Whiteside County.
Total Sites
422
across Whiteside County
Risk Level
Elevated
Highest-severity
6 Superfund sites (none NPL-listed)
Sources Checked
across Whiteside County
Severity Distribution
across Whiteside County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Whiteside County, two things run higher than the national average across Whiteside County — CAFO (7 sites) and PFAS (4 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
CAFO: CAFOs pose a different contamination profile than chemical sources.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Check your specific parcel in Whiteside 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 Whiteside County average
Your land is one point inside Whiteside County
Everything above resolves to Whiteside County as a whole — one PHZM band and one county frost record, read across 438K 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 Whiteside County Average
Whiteside County Average
- ●USDA Zones 5b, averaged across Whiteside County
- ●One soil character for all of Whiteside County
- ●Frost dates read at Whiteside County's scale: Apr 11 to Oct 22
YOUR Parcel
- ✓Your exact zone, not Whiteside County's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Whiteside County
Pull a site-specific report for your exact address in Whiteside County, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Whiteside County averages can't show:
We read public map data around Whiteside County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Whiteside County average
How we know this about Whiteside 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 Whiteside County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Whiteside County
When does frost risk typically end in Whiteside County?
The last hard freeze (28°F) in Whiteside County typically lands around Apr 11, 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 2.
How long is the growing season in Whiteside County?
Measured between 28°F hard freezes, Whiteside County sees about 194 frost-free days — roughly Apr 11 through Oct 22, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 2 to Oct 8, about 159 days.
Is the soil safe to grow vegetables in Whiteside County?
The federal record around Whiteside County is a meaningful one — 422 documented sites, mostly Underground Storage Tanks entries (263), the nearest Underground Storage Tanks record about 1.3 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 Whiteside County's scale — its 5b band and its 194-day season. Your yard writes its own version of Whiteside 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 Whiteside County’s own scale
9 of the readings below were taken at Whiteside County's own scale — its own ~194-day span between 28°F freezes, the 3 most extensive soil series mapped here and 422 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Whiteside County's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Whiteside County's own 28°F hard-freeze dates and its ~194-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Whiteside CountyUSDA NRCS SSURGO
- 422 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Underground Storage Tanks record about 1.3 miles outFederal environmental registers
- Whiteside County's boundary and the 437,823 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~194-day seasonGrowable Ground crop-matching engine
- The 2 ecoregions Whiteside County spans, Central Corn Belt Plains the largestUS EPA Level III Ecoregions
- Open occurrence records documented in Whiteside County for a tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Whiteside 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 Whiteside County — the ~194 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 Whiteside County's 437,823 acreswhy one lot differs from the next →
- Which of those 422 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 Whiteside Countyread your own land →