Grantsburg, Wisconsin, sits in USDA hardiness zone 4a — a zone band wide enough that plant choice, not possibility, is the interesting question.
Among the crops suited to this profile: cabbage, cranberry, turkish rocket, and collard greens. The site-level story — soil, sun, drainage — decides the rest.
Even in Grantsburg, 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 Grantsburg 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 Grantsburg — soil, climate, flood, and parcel records. How we handle your address.
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Grantsburg — the short answer
Grantsburg, Wisconsin: USDA zone 4a, about 160 days between hard freezes, across 2K acres of town.
- USDA zone
- 4a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 30
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 7
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~160
- 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 4a is Grantsburg's average, not your lot's — a low corner or a tree line moves it. Against Grantsburg's 160-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Grantsburg
Each reading below is measured for Grantsburg itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredGrantsburg runs about 160 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
MeasuredGrantsburg sits in USDA hardiness zone 4a.
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 Grantsburg is in
Grantsburg sits in the Northern Lakes and Forests — EPA Level III, inside the wider Northern Forests. That is read at Grantsburg's own centroid rather than borrowed from Burnett County.
What Grows in Grantsburg
Every plant below cleared Grantsburg's own zone 4a and its 160-day season. Each card opens that plant's Wisconsin profile. How we score.
Is it too late to plant in Grantsburg?
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 Apr 2; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 30 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 7 — long-season crops need about 90 days of runway, quick greens only 30. Late in the year the fall bench takes over — quick greens, radishes, and garlic that repays you next summer.
What's on the federal record near Grantsburg
Closest first, within ~10 miles of Grantsburg. Listing isn't leaking, and distance isn't exposure.
- Mcnally Industries IncUnderground Storage Tanks · 1800 ft
- GRANTSBURG SATELLITE SHOPUnderground Storage Tanks · 1800 ft
- Burnett Dairy CoopUnderground Storage Tanks · 1900 ft
- ANDERSON REPAIR & BODY SHOPBrownfields · 1900 ft
- CLOVER BUS SVCBrownfields · 1900 ft
- FIEDLER FORD INCUnderground Storage Tanks · 1900 ft
- NORTHERN MFG. CO., INC.Brownfields · 1900 ft
- CLOVER BUS SERVICEUnderground Storage Tanks · 1900 ft
- FIEDLER FORD INCBrownfields · 2000 ft
- JOHNS SERVICE & REPAIRUnderground Storage Tanks · 2000 ft
- DICKS SUPER VALUEUnderground Storage Tanks · 2000 ft
- PARKER HANNIFIN CORP QUICK COU DIVToxics Release Inventory · 2100 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Grantsburg'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 Grantsburg.
Total Sites
103
within ~10 miles of Grantsburg
Risk Level
Moderate
Highest-severity
3 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Grantsburg
Severity Distribution
within ~10 miles of Grantsburg
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 Grantsburg
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 Grantsburg average
Your land is one point inside Grantsburg
Everything above resolves to Grantsburg 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 Grantsburg Average
Grantsburg Average
- ●USDA Zones 4a, averaged across Grantsburg
- ●One soil character for all of Grantsburg
- ●Frost dates read at Grantsburg's scale: Apr 30 to Oct 7
YOUR Parcel
- ✓Your exact zone, not Grantsburg's 4a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Grantsburg
Pull a site-specific report for your exact address in Grantsburg, Wisconsin — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Grantsburg averages can't show:
We read public map data around Grantsburg — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Grantsburg average
How we know this about Grantsburg
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 Grantsburg’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 Grantsburg
When does frost risk typically end in Grantsburg?
The last hard freeze (28°F) in Grantsburg typically lands around Apr 30, 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 21.
When is the first frost in Grantsburg?
The first hard freeze (28°F) in Grantsburg typically arrives around Oct 7, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 23, so the watching starts about Sep 7 — about 160 days after the spring freeze cleared.
How long is the growing season in Grantsburg?
Measured between 28°F hard freezes, Grantsburg sees about 160 frost-free days — roughly Apr 30 through Oct 7, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 21 to Sep 23, about 125 days.
Is the soil safe to grow vegetables in Grantsburg?
The federal record around Grantsburg shows 103 documented sites, mostly Underground Storage Tanks entries (47), the nearest Underground Storage Tanks record about 0.3 miles 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 Grantsburg?
From about Sep 7 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 7 (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 7. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Grantsburg's scale — its 4a band and its 160-day season. Your yard writes its own version of Grantsburg'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 Grantsburg’s own scale
6 of the readings below were taken at Grantsburg's own scale — its own ~160-day season between 28°F freezes, the 1,945 acres it covers and 103 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Grantsburg's own USDA hardiness band, zones 4aUSDA PHZM 2023
- Grantsburg's own 28°F hard-freeze dates, about Apr 30 and Oct 7 and the ~160-day span between themNOAA 1991–2020 Climate Normals
- 103 documented contamination sites on the federal record near Grantsburg, the closest Underground Storage Tanks record about 0.3 miles out from the town centreFederal environmental registers
- Grantsburg's boundary and the 1,945 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4a and a ~160-day seasonGrowable Ground crop-matching engine
- The ecoregion at Grantsburg's own centroid, the Northern Lakes and ForestsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Grantsburg's 1,945 acres read through its county's SSURGO summaryfrom Burnett County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Burnett 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 Burnett County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Grantsburg's 1,945 acreswhy one lot differs from the next →
- Which side of Grantsburg you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,945 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.3 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 Grantsburg-wide figureread your own land →
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