Walworth County, in Wisconsin, sits in USDA hardiness zone 5b — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
Reliable performers under these conditions include cabbage, cranberry, lavender, and collard greens; what your own ground favors still comes down to its soil, sun, and drainage.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Walworth County holds more than one microclimate.
Soils and elevations shift across Walworth 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 Walworth County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Walworth County — the short answer
Walworth County, Wisconsin: USDA zone 5b, about 191 days between hard freezes, across 355K acres.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 15
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 23
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~191
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 355K 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 Walworth County's average, not your lot's — a low corner or a tree line moves it. Against Walworth County's 191-day season, see what your own ground reads.
Heat in Walworth County
Across a year, Walworth County accumulates about 2,503 growing degree days above 50°F, about 353 more than the middle Wisconsin county — ahead of 68 of Wisconsin’s 72 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 Walworth County
Across Walworth County, the ground is predominantly Alfisols, where Miami, Plano, and Fox are the most extensive named soil series. The soil is generally well drained with a silt loam surface. Topsoil pH runs about 6.5–6.7, neutral. Rainfall drains through hydrologic group B soils.
Soil order
Alfisols
Drainage
Well drained
Prime farmland
50%
Hydric soils
17%
Soil still varies lot by lot — soil types explained.
How the ground varies across Walworth County
The USDA soil survey maps 62% of Walworth County as well drained — but another 34% drains differently: 11% poorly drained, 7% somewhat poorly drained.
Miami is the most extensive named soil at 18% of mapped acres, then Plano (13%) and Fox (9%).
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 Walworth County
Each reading below is measured for Walworth 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 Walworth 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 Walworth County runs about pH 6.5–6.7, 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 17% of Walworth 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
MeasuredWalworth County 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
The kind of country Walworth County is in
Walworth County sits in the Southeastern Wisconsin Till Plains — EPA Level III, inside the wider Eastern Temperate Forests. One consistent ecological setting across the whole county.
What Grows in Walworth County
We scored all 1,086 plants against Walworth County's own USDA zone 5b and its own 191-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 Wisconsin profile.
Is it too late to plant in Walworth County?
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 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. 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 Walworth County
- Japanese beetle2 documented records
- monarch butterfly22 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Walworth County
USGS estimates 196,288 lb of Glyphosate on Walworth County farmland in 2019, its largest by weight, ahead of Metolachlor & Metolachlor-s (67,974 lb) and Metolachlor-s (59,190 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 Walworth County — and how to grow with it.
We checked the federal record across Walworth County — 1,126 documented sites across 7 of the 9 source types we track.
The most significant on record: 5 Superfund sites. 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 Walworth 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 Walworth County
Closest first, across Walworth County. Listing isn't leaking, and distance isn't exposure.
- WILLIAM ROEDERUnderground Storage Tanks · 200 ft
- BOLTON FARMSUnderground Storage Tanks · 200 ft
- MESA INDUSTRIES INCToxics Release Inventory · 600 ft
- PALMER HAMILTON LLCBrownfields · 600 ft
- DUANE KURTHUnderground Storage Tanks · 600 ft
- CONSUMERS COOP WALWORTHUnderground Storage Tanks · 650 ft
- ELKHORN LUMBER CO INCUnderground Storage Tanks · 700 ft
- Speedway #4086Underground Storage Tanks · 750 ft
- DUANE KURTH EXCAVATINGUnderground Storage Tanks · 750 ft
- SPEEDWAY 4086Brownfields · 800 ft
- AG AVIATION SERVICE INCUnderground Storage Tanks · 800 ft
- WEDIGE RADIATOR & AIR CONDITIONING INCBrownfields · 800 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Walworth 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 Walworth County.
Sources Checked
across Walworth County
Severity Distribution
across Walworth County
Highest-Severity Sites
Know Before You Grow
- •Underground tanks leak petroleum as they age — near a former filling station, test the soil.
- •Near a brownfield, raised beds of imported soil give your food clean ground.
- •On a private well, test for nitrates: above 10 mg/L the water needs treatment before irrigating.
Check your specific parcel in Walworth 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 Walworth County average
Your land is one point inside Walworth County
Everything above resolves to Walworth County as a whole — one PHZM band and one county frost record, read across 355K 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 Walworth County Average
Walworth County Average
- ●USDA Zones 5b, averaged across Walworth County
- ●One soil character for all of Walworth County
- ●Frost dates read at Walworth County's scale: Apr 15 to Oct 23
YOUR Parcel
- ✓Your exact zone, not Walworth County's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Walworth County
Pull a site-specific report for your exact address in Walworth County, Wisconsin — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Walworth County averages can't show:
We read public map data around Walworth County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Walworth County average
How we know this about Walworth 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 Walworth County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Walworth County
When does frost risk typically end in Walworth County?
The last hard freeze (28°F) in Walworth County 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.
How long is the growing season in Walworth County?
Measured between 28°F hard freezes, Walworth County 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 Walworth County?
The federal record around Walworth County is a meaningful one — 1,126 documented sites, mostly Underground Storage Tanks entries (595), the nearest Underground Storage Tanks record under a tenth of a mile 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 Walworth County's scale — its 5b band and its 191-day season. Your yard writes its own version of Walworth 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 Wisconsin's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Walworth County’s own scale
9 of the readings below were taken at Walworth County's own scale — its own ~191-day span between 28°F freezes, the 3 most extensive soil series mapped here and 1,126 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Walworth County's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Walworth County's own 28°F hard-freeze dates and its ~191-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Walworth CountyUSDA NRCS SSURGO
- 1,126 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Underground Storage Tanks record under a tenth of a mile outFederal environmental registers
- Walworth County's boundary and the 355,479 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~191-day seasonGrowable Ground crop-matching engine
- Walworth County sitting wholly inside the Southeastern Wisconsin Till PlainsUS EPA Level III Ecoregions
- Open occurrence records documented in Walworth County for 2 tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Walworth County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every Wisconsin grower plans around — written at state scale, so they stay on the state guidefrom Wisconsin
What this page can’t tell you
- How the season shifts across Walworth County — the ~191 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 Walworth County's 355,479 acreswhy one lot differs from the next →
- Which of those 1,126 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 Walworth Countyread your own land →