Carlton, Minnesota, sits in USDA hardiness zone 4a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
These conditions suit cabbage, cranberry, cilantro, and collard greens — a starting list any specific site will trim or extend with its own soil, sun, and drainage.
Even in Carlton, 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 Carlton 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 Carlton — soil, climate, flood, and parcel records. How we handle your address.
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Carlton — the short answer
Carlton, Minnesota: USDA zone 4a, about 148 days between hard freezes, across 2K acres of city.
- USDA zone
- 4a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 12
- 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
- ~148
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City 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 Carlton's average, not your lot's — a low corner or a tree line moves it. Against Carlton's 148-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Carlton
Each reading below is measured for Carlton itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredCarlton runs about 148 days between hard freezes — a short growing season.
Long-maturing crops like melons, sweet potatoes, and winter squash can run out of runway before the first hard freeze, ripening late or not at all.
Lead with fast-maturing varieties, and stretch the season on both ends with cold frames, low tunnels, or a greenhouse.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredCarlton 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 Carlton is in
Carlton sits in the Northern Lakes and Forests — EPA Level III, inside the wider Northern Forests. That is read at Carlton's own centroid rather than borrowed from Carlton County.
What Grows in Carlton
Every plant below cleared Carlton's own zone 4a and its 148-day season. Each card opens that plant's Minnesota profile. How we score.
Is it too late to plant in Carlton?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Apr 14; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 12 (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. Short seasons reward decisiveness — quick-maturing varieties late, hardy greens under cover, and next year’s garlic in the ground before it closes.
What's on the federal record near Carlton
Closest first, within ~10 miles of Carlton. Listing isn't leaking, and distance isn't exposure.
- Carlton Self ServiceUnderground Storage Tanks · 2100 ft
- CHEMSTAR PRODUCTS COMPANYBrownfields · 2500 ft
- CHEMSTAR PRODUCTS COMPANYToxics Release Inventory · 2500 ft
- DULUTH LTLBrownfields · 0.5 mi
- BNSF RAILWAY BRIDGES & BUILDINGSBrownfields · 0.6 mi
- JRS CARLTON SERVICEBrownfields · 0.6 mi
- Carlton MotorwerksUnderground Storage Tanks · 0.6 mi
- PRINT CORPBrownfields · 0.6 mi
- MINNESOTA POWER INC - THOMSON HYDRO STNBrownfields · 0.7 mi
- CARLTON COUNTYBrownfields · 0.7 mi
- Harolds ServiceUnderground Storage Tanks · 0.7 mi
- HAROLDS SERVICEBrownfields · 0.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Carlton'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 Carlton.
Total Sites
393
within ~10 miles of Carlton
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Carlton
Severity Distribution
within ~10 miles of Carlton
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Carlton, Nitrate runs higher than the national average — 104 sites within ~10 miles of Carlton. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Carlton
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 Carlton average
Your land is one point inside Carlton
Everything above resolves to Carlton 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 city 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 Carlton Average
Carlton Average
- ●USDA Zones 4a, averaged across Carlton
- ●One soil character for all of Carlton
- ●Frost dates read at Carlton's scale: May 12 to Oct 7
YOUR Parcel
- ✓Your exact zone, not Carlton's 4a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Carlton
Pull a site-specific report for your exact address in Carlton, Minnesota — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Carlton averages can't show:
We read public map data around Carlton — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Carlton average
How we know this about Carlton
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this city’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Carlton’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 city grain anywhere on this page — there is no city-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 Carlton
When does frost risk typically end in Carlton?
The last hard freeze (28°F) in Carlton typically lands around May 12, 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 Jun 2.
When is the first frost in Carlton?
The first hard freeze (28°F) in Carlton 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 148 days after the spring freeze cleared.
How long is the growing season in Carlton?
Measured between 28°F hard freezes, Carlton sees about 148 frost-free days — roughly May 12 through Oct 7, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 2 to Sep 23, about 113 days.
Is the soil safe to grow vegetables in Carlton?
The federal record around Carlton is a meaningful one — 393 documented sites, mostly Brownfields entries (163), the nearest Underground Storage Tanks record about 0.4 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 gardeners stretch the season in Carlton?
With about 148 frost-free days between hard freezes, Carlton rewards the classic extension moves: floating row cover buys roughly two to four extra weeks at each shoulder — on this season that is a working window nearer 176 to 204 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 12 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Carlton's scale — its 4a band and its 148-day season. Your yard writes its own version of Carlton'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 Carlton’s own scale
6 of the readings below were taken at Carlton's own scale — its own ~148-day season between 28°F freezes, the 2,435 acres it covers and 393 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Carlton's own USDA hardiness band, zones 4aUSDA PHZM 2023
- Carlton's own 28°F hard-freeze dates, about May 12 and Oct 7 and the ~148-day span between themNOAA 1991–2020 Climate Normals
- 393 documented contamination sites on the federal record near Carlton, the closest Underground Storage Tanks record about 0.4 miles out from the town centreFederal environmental registers
- Carlton's boundary and the 2,435 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4a and a ~148-day seasonGrowable Ground crop-matching engine
- The ecoregion at Carlton'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 Carlton's 2,435 acres read through its county's SSURGO summaryfrom Carlton County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Carlton County
- The growing challenges every Minnesota grower plans around — written at state scale, so they stay on the state guidefrom Minnesota
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Carlton County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Carlton's 2,435 acreswhy one lot differs from the next →
- Which side of Carlton you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 2,435 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.4 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 Carlton-wide figureread your own land →
More in Minnesota
Wider growing context
What grows across MinnesotaCarlton sits outside our named growing regions, so Minnesota as a whole is its closest context here.