Hermantown, Minnesota, sits in USDA hardiness zone 4b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Growers here do well with cabbage, cranberry, turkish rocket, and collard greens — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Even in Hermantown, 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 Hermantown 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 Hermantown — soil, climate, flood, and parcel records. How we handle your address.
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Hermantown — the short answer
Hermantown, Minnesota: USDA zone 4b, about 166 days between hard freezes, across 22K acres of city.
- USDA zone
- 4b
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 1
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 14
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~166
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 22K 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 4b is Hermantown's average, not your lot's — a low corner or a tree line moves it. Against Hermantown's 166-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Hermantown
Each reading below is measured for Hermantown itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredHermantown runs about 166 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
MeasuredHermantown sits in USDA hardiness zone 4b.
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 Hermantown is in
Hermantown sits in the Northern Lakes and Forests — EPA Level III, inside the wider Northern Forests. That is read at Hermantown's own centroid rather than borrowed from St. Louis County.
What Grows in Hermantown
Every plant below cleared Hermantown's own zone 4b and its 166-day season. Each card opens that plant's Minnesota profile. How we score.
Is it too late to plant in Hermantown?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Apr 3; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 1 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 14 — 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 Hermantown
Closest first, within ~10 miles of Hermantown. Listing isn't leaking, and distance isn't exposure.
- HERMANTOWN CITY OFBrownfields · 2500 ft
- TWIN PORTS TRUCK & EQUIPMENTBrownfields · 0.6 mi
- HERMANTOWN CITY OF POLICE DEPARTMENTBrownfields · 1.1 mi
- THE PILLARS OF HERMANTOWNBrownfields · 1.2 mi
- Hermantown School Bus GarageUnderground Storage Tanks · 1.3 mi
- Isd 700 HermantownUnderground Storage Tanks · 1.4 mi
- Hermantown Schools Admin bldg, MW-1Nitrate · 1.4 mi
- PETSMART 2735Brownfields · 1.4 mi
- ISD 700 HERMANTOWN HIGH SCHOOLBrownfields · 1.5 mi
- DOCTOR MOSQUITOBrownfields · 1.7 mi
- TBS 1Brownfields · 1.9 mi
- NORTHSTAR INSULATING SYSTEMS INCBrownfields · 1.9 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Hermantown'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 Hermantown.
Sources Checked
within ~10 miles of Hermantown
Severity Distribution
within ~10 miles of Hermantown
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Hermantown, Brownfields runs higher than the national average — 810 sites within ~10 miles of Hermantown. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Brownfields: Brownfield sites are former commercial or industrial properties where legacy soil contamination (heavy metals, PAHs, petroleum compounds) may persist.
Check EPA brownfield remediation status — many sites have completed cleanup with institutional controls.
Check your specific parcel in Hermantown
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 Hermantown average
Your land is one point inside Hermantown
Everything above resolves to Hermantown as a whole — one PHZM band and one 28°F frost record, read across 22K 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 Hermantown Average
Hermantown Average
- ●USDA Zones 4b, averaged across Hermantown
- ●One soil character for all of Hermantown
- ●Frost dates read at Hermantown's scale: May 1 to Oct 14
YOUR Parcel
- ✓Your exact zone, not Hermantown's 4b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Hermantown
Pull a site-specific report for your exact address in Hermantown, Minnesota — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Hermantown averages can't show:
We read public map data around Hermantown — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Hermantown average
How we know this about Hermantown
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 Hermantown’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 Hermantown
When does frost risk typically end in Hermantown?
The last hard freeze (28°F) in Hermantown typically lands around May 1, 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 22.
When is the first frost in Hermantown?
The first hard freeze (28°F) in Hermantown typically arrives around Oct 14, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 30, so the watching starts about Sep 14 — about 166 days after the spring freeze cleared.
How long is the growing season in Hermantown?
Measured between 28°F hard freezes, Hermantown sees about 166 frost-free days — roughly May 1 through Oct 14, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 22 to Sep 30, about 131 days.
Is the soil safe to grow vegetables in Hermantown?
The federal record around Hermantown is a meaningful one — 1,340 documented sites, mostly Brownfields entries (810), the nearest Brownfields record about 0.5 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 Hermantown?
From about Sep 14 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 14 (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 14. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Hermantown's scale — its 4b band and its 166-day season. Your yard writes its own version of Hermantown'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 Hermantown’s own scale
6 of the readings below were taken at Hermantown's own scale — its own ~166-day season between 28°F freezes, the 21,991 acres it covers and 1,340 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Hermantown's own USDA hardiness band, zones 4bUSDA PHZM 2023
- Hermantown's own 28°F hard-freeze dates, about May 1 and Oct 14 and the ~166-day span between themNOAA 1991–2020 Climate Normals
- 1,340 documented contamination sites on the federal record near Hermantown, the closest Brownfields record about 0.5 miles out from the town centreFederal environmental registers
- Hermantown's boundary and the 21,991 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4b and a ~166-day seasonGrowable Ground crop-matching engine
- The ecoregion at Hermantown'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 Hermantown's 21,991 acres read through its county's SSURGO summaryfrom St. Louis County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom St. Louis 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 St. Louis County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Hermantown's 21,991 acreswhy one lot differs from the next →
- Which side of Hermantown you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 21,991 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields record about 0.5 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 Hermantown-wide figureread your own land →
More in Minnesota
Wider growing context
What grows across MinnesotaHermantown sits outside our named growing regions, so Minnesota as a whole is its closest context here.