Plain, Wisconsin, sits in USDA hardiness zone 5a — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
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.
Even in Plain, no two yards are alike.
A low spot, a south-facing slope, or a stand of trees moves the frost date and sun across a single Plain lot. 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 Plain — soil, climate, flood, and parcel records. How we handle your address.
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Plain — the short answer
Plain, Wisconsin: USDA zone 5a, about 177 days between hard freezes, across 582 acres of town.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 21
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 15
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~177
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 582 acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are this town’s own 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 Plain's average, not your lot's — a low corner or a tree line moves it. Against Plain's 177-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Plain
Each reading below is measured for Plain itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredPlain runs about 177 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
Winter hardiness
MeasuredPlain sits in USDA hardiness zone 5a.
The zone sets which perennials, shrubs, and fruit trees live through an average winter here — a plant rated for a colder zone is a safe bet, one rated warmer needs winter protection or gets treated as an annual.
Match perennials and fruit to the zone before you buy, so nothing you plant is a gamble against the cold.
USDA PHZM 2023
The kind of country Plain is in
Plain sits in the Driftless Area — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Plain's own centroid rather than borrowed from Sauk County.
What Grows in Plain
Every plant below cleared Plain's own zone 5a and its 177-day season. Each card opens that plant's Wisconsin profile. How we score.
Is it too late to plant in Plain?
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 24; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 21 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 15 — 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.
What's on the federal record near Plain
Closest first, within ~10 miles of Plain. Listing isn't leaking, and distance isn't exposure.
- Cenex Consumers CoopUnderground Storage Tanks · 400 ft
- PLAIN CLINICBrownfields · 600 ft
- KRAEMER BROTHERS INCUnderground Storage Tanks · 600 ft
- Umhoefer Lumber & SupplyUnderground Storage Tanks · 600 ft
- PLAIN POST OFFICEUnderground Storage Tanks · 650 ft
- Plain Kwik StopUnderground Storage Tanks · 750 ft
- EDWARD KRAEMER & SONS INCUnderground Storage Tanks · 1000 ft
- EDWARD KRAEMER & SONS INCBrownfields · 1100 ft
- TOWN OF FRANKLINUnderground Storage Tanks · 1200 ft
- KRAEMER COMPANY CRUSHING PLANT #2Brownfields · 1200 ft
- JOHN E SCHMITZUnderground Storage Tanks · 1300 ft
- MATHY CONSTRUCTION - PLAIN SHOPBrownfields · 1300 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Plain'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 Plain.
Total Sites
137
within ~10 miles of Plain
Risk Level
Moderate
Highest-severity
5 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Plain
Severity Distribution
within ~10 miles of Plain
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Plain, two things run higher than the national average within ~10 miles of Plain — CAFO (3 sites) and Underground Storage Tanks (88 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.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Plain
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 Plain average
Your land is one point inside Plain
Everything above resolves to Plain as a whole — one PHZM band and one 28°F frost record, read across 582 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 town 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 local average.
Your Lot vs the Plain Average
Plain Average
- ●USDA Zones 5a, averaged across Plain
- ●One soil character for all of Plain
- ●Frost dates read at Plain's scale: Apr 21 to Oct 15
YOUR Parcel
- ✓Your exact zone, not Plain's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Plain
Pull a site-specific report for your exact address in Plain, Wisconsin — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Plain averages can't show:
We read public map data around Plain — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Plain average
How we know this about Plain
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this town’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Plain’s own record; boundaries and acreage from US Census TIGER/Line 2025; the contamination records from the federal sources named in their beats above. Soil is not read at town grain anywhere on this page — there is no town-resolution survey in our data, which is why you will find no soil grid here rather than a statewide one wearing a local label. The resolution ledger below names every figure this page inherited.
Common questions about Plain
When does frost risk typically end in Plain?
The last hard freeze (28°F) in Plain typically lands around Apr 21, 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 12.
When is the first frost in Plain?
The first hard freeze (28°F) in Plain typically arrives around Oct 15, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 1, so the watching starts about Sep 15 — about 177 days after the spring freeze cleared.
How long is the growing season in Plain?
Measured between 28°F hard freezes, Plain sees about 177 frost-free days — roughly Apr 21 through Oct 15, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 12 to Oct 1, about 142 days.
Is the soil safe to grow vegetables in Plain?
The federal record around Plain shows 137 documented sites, mostly Underground Storage Tanks entries (88), the nearest Underground Storage Tanks record under a tenth of a mile out — a typical footprint for a growing area, and proximity to a documented site is information, not a diagnosis of any one yard. It's worth seeing which recorded sites sit closest to where you grow, and testing the soil before new food beds near any of them.
How do I protect my plants from frost in Plain?
From about Sep 15 the job here turns from planting to protecting — the last start even a 30-day crop can finish. As the season closes around the first 28°F hard freeze near Oct 15 (NOAA 1991–2020 climate normals), three moves buy time: row cover or an old sheet over tender plants on still, clear nights; water the soil the afternoon before a freeze, so it holds warmth overnight; and harvest tomatoes, peppers and basil before Oct 15. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Plain's scale — its 5a band and its 177-day season. Your yard writes its own version of Plain's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
What this page reads at Plain’s own scale
6 of the readings below were taken at Plain's own scale — its own ~177-day season between 28°F freezes, the 582 acres it covers and 137 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Plain's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Plain's own 28°F hard-freeze dates, about Apr 21 and Oct 15 and the ~177-day span between themNOAA 1991–2020 Climate Normals
- 137 documented contamination sites on the federal record near Plain, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- Plain's boundary and the 582 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~177-day seasonGrowable Ground crop-matching engine
- The ecoregion at Plain's own centroid, the Driftless AreaUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Plain's 582 acres read through its county's SSURGO summaryfrom Sauk County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Sauk County
- The growing challenges every Wisconsin grower plans around — written at state scale, so they stay on the state guidefrom Wisconsin
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Sauk County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Plain's 582 acreswhy one lot differs from the next →
- Which side of Plain you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 582 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record under a tenth of a mile out, measured from the town centrehow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — measured at your address, and averaged away by any Plain-wide figureread your own land →
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