Green Lake County, in Wisconsin, sits in USDA hardiness zone 5a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Well-matched crops include cabbage, cranberry, lavender, and collard greens, and the gap between "grows in the area" and "grows in your yard" is closed by soil, sun, and drainage.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Green Lake County holds more than one microclimate.
Soils and elevations shift across Green Lake 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 Green Lake County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Green Lake County — the short answer
Green Lake County, Wisconsin: USDA zone 5a, about 180 days between hard freezes, across 224K acres.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 19
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 16
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~180
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 224K 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 5a is Green Lake County's average, not your lot's — a low corner or a tree line moves it. Against Green Lake County's 180-day season, see what your own ground reads.
Heat in Green Lake County
Across a year, Green Lake County accumulates about 2,277 growing degree days above 50°F, about 127 more than the middle Wisconsin county — ahead of 48 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 Green Lake County
Across Green Lake County, the ground is predominantly Mollisols, where Kidder, Plano, and Houghton are the most extensive named soil series. The soil is generally well drained with a silt loam surface. Topsoil pH runs about 6.5–7.0, neutral. Rainfall drains through hydrologic group B soils.
Soil order
Mollisols
Drainage
Well drained
Prime farmland
38%
Hydric soils
31%
Soil still varies lot by lot — soil types explained.
How the ground varies across Green Lake County
The USDA soil survey maps 49% of Green Lake County as well drained — but another 43% drains differently: 16% poorly drained, 14% very poorly drained.
Kidder is the most extensive named soil at 12% of mapped acres, then Plano (10%) and Houghton (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 Green Lake County
Each reading below is measured for Green Lake 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 Green Lake 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 Green Lake County runs about pH 6.5–7.0, 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 31% of Green Lake 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
MeasuredGreen Lake County runs about 180 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 Green Lake County is in
Green Lake County spans 2 EPA Level III ecoregions — Southeastern Wisconsin Till Plains (88%) and North Central Hardwood Forests (12%). 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 Green Lake County
We scored all 1,086 plants against Green Lake County's own USDA zone 5a and its own 180-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 Green Lake County?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Mar 22; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 19 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 16 — 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.
Documented around Green Lake County
Spotted lanternfly documented 13 miles from Green Lake County, first recorded 2023. What to watch for.
- Japanese beetle1 documented records
- monarch butterfly7 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Green Lake County
USGS estimates 81,184 lb of Glyphosate on Green Lake County farmland in 2019, its largest by weight, ahead of Metolachlor & Metolachlor-s (45,522 lb) and Metolachlor-s (26,165 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 Green Lake County — and how to grow with it.
We checked the federal record across Green Lake County — 353 documented sites across 6 of the 9 source types we track.
The most significant on record: 1 Superfund site (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 Green Lake 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 Green Lake County
Closest first, across Green Lake County. Listing isn't leaking, and distance isn't exposure.
- CENTER HOUSEUnderground Storage Tanks · 1.0 mi
- TOWN OF GREEN LAKEUnderground Storage Tanks · 1.8 mi
- LINDAS TERRACE TAPUnderground Storage Tanks · 2.5 mi
- MITCHELL PROPERTYUnderground Storage Tanks · 2.7 mi
- GARY ZIMMERMANUnderground Storage Tanks · 2.8 mi
- Melvin ChertackUnderground Storage Tanks · 2.9 mi
- LAKE VIEW INN LLCUnderground Storage Tanks · 3.1 mi
- BEN OLMSTEADUnderground Storage Tanks · 3.4 mi
- The LandingUnderground Storage Tanks · 3.6 mi
- CLYDE ALSHANSKIUnderground Storage Tanks · 3.6 mi
- WELKS LANDINGUnderground Storage Tanks · 3.6 mi
- SADIE HAWKS ANTIQUESUnderground Storage Tanks · 3.9 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Green Lake 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 Green Lake County.
Total Sites
353
across Green Lake County
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
across Green Lake County
Severity Distribution
across Green Lake County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Green Lake County, two things run higher than the national average across Green Lake County — Underground Storage Tanks (258 sites) and CAFO (3 sites). That's not a problem with your land — it's information about it.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
CAFO: CAFOs pose a different contamination profile than chemical sources.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Check your specific parcel in Green Lake 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 Green Lake County average
Your land is one point inside Green Lake County
Everything above resolves to Green Lake County as a whole — one PHZM band and one county frost record, read across 224K 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 Green Lake County Average
Green Lake County Average
- ●USDA Zones 5a, averaged across Green Lake County
- ●One soil character for all of Green Lake County
- ●Frost dates read at Green Lake County's scale: Apr 19 to Oct 16
YOUR Parcel
- ✓Your exact zone, not Green Lake County's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Green Lake County
Pull a site-specific report for your exact address in Green Lake County, Wisconsin — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Green Lake County averages can't show:
We read public map data around Green Lake County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Green Lake County average
How we know this about Green Lake 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 Green Lake County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Green Lake County
When does frost risk typically end in Green Lake County?
The last hard freeze (28°F) in Green Lake County typically lands around Apr 19, 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 10.
How long is the growing season in Green Lake County?
Measured between 28°F hard freezes, Green Lake County sees about 180 frost-free days — roughly Apr 19 through Oct 16, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 10 to Oct 2, about 145 days.
Is the soil safe to grow vegetables in Green Lake County?
The federal record around Green Lake County is a meaningful one — 353 documented sites, mostly Underground Storage Tanks entries (258), the nearest Underground Storage Tanks record about 1.0 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 Green Lake County's scale — its 5a band and its 180-day season. Your yard writes its own version of Green Lake 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 Green Lake County’s own scale
9 of the readings below were taken at Green Lake County's own scale — its own ~180-day span between 28°F freezes, the 3 most extensive soil series mapped here and 353 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Green Lake County's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Green Lake County's own 28°F hard-freeze dates and its ~180-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Green Lake CountyUSDA NRCS SSURGO
- 353 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Underground Storage Tanks record about 1.0 miles outFederal environmental registers
- Green Lake County's boundary and the 223,706 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~180-day seasonGrowable Ground crop-matching engine
- The 2 ecoregions Green Lake County spans, Southeastern Wisconsin Till Plains the largestUS EPA Level III Ecoregions
- Open occurrence records documented in Green Lake County for 2 tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Green Lake 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 Green Lake County — the ~180 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 Green Lake County's 223,706 acreswhy one lot differs from the next →
- Which of those 353 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 Green Lake Countyread your own land →