Jackson, Wisconsin, sits in USDA hardiness zone 5b — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Growers here do well with cabbage, cranberry, lavender, and collard greens — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Even in Jackson, 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 Jackson 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 Jackson — soil, climate, flood, and parcel records. How we handle your address.
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Jackson — the short answer
Jackson, Wisconsin: USDA zone 5b, about 186 days between hard freezes, across 2K acres of town.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 17
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 20
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~186
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 2K 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 5b is Jackson's average, not your lot's — a low corner or a tree line moves it. Against Jackson's 186-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Jackson
Each reading below is measured for Jackson itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredJackson runs about 186 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
MeasuredJackson sits in USDA hardiness zone 5b.
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 Jackson is in
Jackson sits in the Southeastern Wisconsin Till Plains — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Jackson's own centroid rather than borrowed from Washington County.
What Grows in Jackson
Every plant below cleared Jackson's own zone 5b and its 186-day season. Each card opens that plant's Wisconsin profile. How we score.
Is it too late to plant in Jackson?
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 20; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 17 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 20 — long-season crops need about 90 days of runway, quick greens only 30. The tail of the season still works: sixty-day crops into late summer, quick greens after, garlic last of all.
What's on the federal record near Jackson
Closest first, within ~10 miles of Jackson. Listing isn't leaking, and distance isn't exposure.
- WN-10/20E/19-0054Nitrate · 900 ft
- FILTER OIL INCUnderground Storage Tanks · 1000 ft
- JACKSON MILL INCUnderground Storage Tanks · 1300 ft
- SIERRA GRINDING WHEEL INCToxics Release Inventory · 1400 ft
- JACKSON COUnderground Storage Tanks · 1500 ft
- WN-10/20E/19-0418Nitrate · 1500 ft
- MILLER MONUMENTSUnderground Storage Tanks · 1500 ft
- SNAK SHAKUnderground Storage Tanks · 1600 ft
- Davids Star Lutheran ChurchUnderground Storage Tanks · 1700 ft
- TIMS LAWN MAINTENANCEUnderground Storage Tanks · 1700 ft
- East Side MartUnderground Storage Tanks · 1700 ft
- WN-10/20E/18-0025Nitrate · 2100 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Jackson'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 Jackson.
Sources Checked
within ~10 miles of Jackson
Severity Distribution
within ~10 miles of Jackson
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Jackson, Toxics Release Inventory runs higher than the national average — 74 sites within ~10 miles of Jackson. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Toxics Release Inventory: TRI facilities report annual chemical releases to air, water, and land.
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Check your specific parcel in Jackson
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 Jackson average
Your land is one point inside Jackson
Everything above resolves to Jackson as a whole — one PHZM band and one 28°F frost record, read across 2K 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 Jackson Average
Jackson Average
- ●USDA Zones 5b, averaged across Jackson
- ●One soil character for all of Jackson
- ●Frost dates read at Jackson's scale: Apr 17 to Oct 20
YOUR Parcel
- ✓Your exact zone, not Jackson's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Jackson
Pull a site-specific report for your exact address in Jackson, Wisconsin — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Jackson averages can't show:
We read public map data around Jackson — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Jackson average
How we know this about Jackson
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 Jackson’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 Jackson
When does frost risk typically end in Jackson?
The last hard freeze (28°F) in Jackson typically lands around Apr 17, 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 8.
When is the first frost in Jackson?
The first hard freeze (28°F) in Jackson typically arrives around Oct 20, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 6, so the watching starts about Sep 20 — about 186 days after the spring freeze cleared.
How long is the growing season in Jackson?
Measured between 28°F hard freezes, Jackson sees about 186 frost-free days — roughly Apr 17 through Oct 20, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 8 to Oct 6, about 151 days.
Is the soil safe to grow vegetables in Jackson?
The federal record around Jackson is a meaningful one — 1,188 documented sites, mostly Underground Storage Tanks entries (535), the nearest Nitrate record about 0.2 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.
How do I protect my plants from frost in Jackson?
From about Sep 20 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 20 (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 20. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Jackson's scale — its 5b band and its 186-day season. Your yard writes its own version of Jackson'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 Jackson’s own scale
6 of the readings below were taken at Jackson's own scale — its own ~186-day season between 28°F freezes, the 2,474 acres it covers and 1,188 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Jackson's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Jackson's own 28°F hard-freeze dates, about Apr 17 and Oct 20 and the ~186-day span between themNOAA 1991–2020 Climate Normals
- 1,188 documented contamination sites on the federal record near Jackson, the closest Nitrate record about 0.2 miles out from the town centreFederal environmental registers
- Jackson's boundary and the 2,474 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~186-day seasonGrowable Ground crop-matching engine
- The ecoregion at Jackson's own centroid, the Southeastern Wisconsin Till PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Jackson's 2,474 acres read through its county's SSURGO summaryfrom Washington County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Washington 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 Washington County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Jackson's 2,474 acreswhy one lot differs from the next →
- Which side of Jackson you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 2,474 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate record about 0.2 miles 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 Jackson-wide figureread your own land →
More in Wisconsin
Wider growing context
What grows across WisconsinJackson sits outside our named growing regions, so Wisconsin as a whole is its closest context here.
Nearby growing guides