Knife River, 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.
On paper, cabbage, cranberry, turkish rocket, and collard greens all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Even in Knife River, 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 Knife River 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 Knife River — soil, climate, flood, and parcel records. How we handle your address.
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Knife River — the short answer
Knife River, Minnesota: USDA zone 4b, about 175 days between hard freezes, across 426 acres of town.
- 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 23
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~175
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 426 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 Knife River's average, not your lot's — a low corner or a tree line moves it. Against Knife River's 175-day season, see what your own ground reads.
Your town runs its own season
Knife River's own 30-year record measures about 175 days between 28°F killing freezes — 38 days longer than Lake County's ~137. Both are measured records, not estimates.
That gap is the whole reason a county average can mislead here. Plant against Knife River's ~175-day season rather than the county figure — and the sun, slope and cold-air drainage on your specific lot move it again.
NOAA Regional Climate Centers ACIS (1991–2020), 30-year daily minimum record. Both figures are measured records — this town’s own and its county’s. A town with no record of its own is absent here rather than estimated.
Soil varies lot by lot — soil types explained.
What this means for growing in Knife River
Each reading below is measured for Knife River itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredKnife River runs about 175 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
MeasuredKnife River 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 Knife River is in
Knife River sits in the Northern Lakes and Forests — EPA Level III, inside the wider Northern Forests. That is read at Knife River's own centroid rather than borrowed from Lake County.
What Grows in Knife River
Every plant below cleared Knife River's own zone 4b and its 175-day season. Each card opens that plant's Minnesota profile. How we score.
Is it too late to plant in Knife River?
For most of the year, no — what changes is which crops still fit the days remaining. 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 23 — 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 Knife River
Closest first, within ~10 miles of Knife River. Listing isn't leaking, and distance isn't exposure.
- KNIFE RIVER MARINABrownfields · 1200 ft
- COOLIDGE MACHINE INCBrownfields · 1500 ft
- MDNR GOOSEBERRY FALLS STATE PARKBrownfields · 1.7 mi
- Sonju Two HarborsUnderground Storage Tanks · 2.4 mi
- LAKE COUNTY VETERINARY CLINICBrownfields · 3.0 mi
- J & K PROFESSIONAL SERVICESBrownfields · 4.0 mi
- VAN TECHNOLOGIES INCBrownfields · 4.7 mi
- NORTHSHORE WOOD PRODUCTSBrownfields · 4.7 mi
- Bomarc PropertiesUnderground Storage Tanks · 4.8 mi
- Clover Valley General StoreUnderground Storage Tanks · 4.9 mi
- SONJU TWO HARBORSBrownfields · 5.4 mi
- FRENCH RIVER SUBSTATIONBrownfields · 5.5 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Knife River'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 Knife River.
Total Sites
115
within ~10 miles of Knife River
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Knife River
Severity Distribution
within ~10 miles of Knife River
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Knife River, Brownfields runs higher than the national average — 67 sites within ~10 miles of Knife River. 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 Knife River
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 Knife River average
Your land is one point inside Knife River
Everything above resolves to Knife River as a whole — and this is a town whose own 30-year record already runs a season its county’s does not. Your parcel sits at one point inside even that. 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 Knife River Average
Knife River Average
- ●USDA Zones 4b, averaged across Knife River
- ●One soil character for all of Knife River
- ●Frost dates read at Knife River's scale: May 1 to Oct 23
YOUR Parcel
- ✓Your exact zone, not Knife River's 4b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Knife River
Pull a site-specific report for your exact address in Knife River, Minnesota — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Knife River averages can't show:
We read public map data around Knife River — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Knife River average
How we know this about Knife River
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 Knife River’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 Knife River
When does frost risk typically end in Knife River?
The last hard freeze (28°F) in Knife River 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 Knife River?
The first hard freeze (28°F) in Knife River typically arrives around Oct 23, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 9, so the watching starts about Sep 23 — about 175 days after the spring freeze cleared.
How long is the growing season in Knife River?
Measured between 28°F hard freezes, Knife River sees about 175 frost-free days — roughly May 1 through Oct 23, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 22 to Oct 9, about 140 days.
Is the soil safe to grow vegetables in Knife River?
The federal record around Knife River is a meaningful one — 115 documented sites, mostly Brownfields entries (67), the nearest Brownfields 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 Knife River?
From about Sep 23 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 23 (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 23. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Knife River's scale — its 4b band and its 175-day season. Your yard writes its own version of Knife River'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 Knife River’s own scale
6 of the readings below were taken at Knife River's own scale — its own ~175-day season between 28°F freezes, the 426 acres it covers and 115 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Knife River's own USDA hardiness band, zones 4bUSDA PHZM 2023
- Knife River's own 28°F hard-freeze dates, about May 1 and Oct 23 and the ~175-day span between themNOAA 1991–2020 Climate Normals
- 115 documented contamination sites on the federal record near Knife River, the closest Brownfields record about 0.2 miles out from the town centreFederal environmental registers
- Knife River's boundary and the 426 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4b and a ~175-day seasonGrowable Ground crop-matching engine
- The ecoregion at Knife River'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 Knife River's 426 acres read through its county's SSURGO summaryfrom Lake County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Lake 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 Lake County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Knife River's 426 acreswhy one lot differs from the next →
- Which side of Knife River you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 426 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields 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 Knife River-wide figureread your own land →
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