Kerr, Montana, sits in USDA hardiness zone 6a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
Expect cabbage, blackberry, california poppy, and collard greens to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
Even in Kerr, 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 Kerr 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 Kerr — soil, climate, flood, and parcel records. How we handle your address.
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Kerr — the short answer
Kerr, Montana: USDA zone 6a, about 169 days between hard freezes, across 582 acres of town.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 26
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 12
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~169
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 582 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 6a is Kerr's average, not your lot's — a low corner or a tree line moves it. Against Kerr's 169-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Kerr
Each reading below is measured for Kerr itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredKerr runs about 169 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
MeasuredKerr sits in USDA hardiness zone 6a.
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 Kerr is in
Kerr sits in the Northern Rockies — EPA Level III, inside the wider Northwestern Forested Mountains. That is read at Kerr's own centroid rather than borrowed from Lake County.
What Grows in Kerr
Every plant below cleared Kerr's own zone 6a and its 169-day season. Each card opens that plant's Montana profile. How we score.
Is it too late to plant in Kerr?
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 Mar 29; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 26 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 12 — long-season crops need about 90 days of runway, quick greens only 30. As the window narrows, the plantings just get faster — fall brassicas, then greens, then garlic to finish.
What's on the federal record near Kerr
Closest first, within ~10 miles of Kerr. Listing isn't leaking, and distance isn't exposure.
- 22N20W17DCAB01Nitrate · 0.9 mi
- ST. JOSEPH MEDICAL CENTERBrownfields · 1.0 mi
- POLSON AIRPORTUnderground Storage Tanks · 1.2 mi
- POLSON CITY SHOPBrownfields · 1.2 mi
- KERR PLANTUnderground Storage Tanks · 1.2 mi
- FLATHEAD LAKE RV RESORTUnderground Storage Tanks · 1.2 mi
- THE MARTA CORPUnderground Storage Tanks · 1.2 mi
- BLUE BAY RESORTUnderground Storage Tanks · 1.2 mi
- MOUNTAIN WEST CO OP POLSONUnderground Storage Tanks · 1.2 mi
- ROLFSON BUILDING SUPPLYUnderground Storage Tanks · 1.2 mi
- BJORK DISTRIBUTING INC 1ST STREET EASTUnderground Storage Tanks · 1.2 mi
- NEWGARD OIL CO INCUnderground Storage Tanks · 1.3 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Kerr'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 Kerr.
Total Sites
127
within ~10 miles of Kerr
Risk Level
Elevated
Highest-severity
2 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Kerr
Severity Distribution
within ~10 miles of Kerr
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Kerr, Nitrate runs higher than the national average — 48 sites within ~10 miles of Kerr. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
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 Kerr
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 Kerr average
Your land is one point inside Kerr
Everything above resolves to Kerr as a whole — one PHZM band and one 28°F frost record, read across 582 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 Kerr Average
Kerr Average
- ●USDA Zones 6a, averaged across Kerr
- ●One soil character for all of Kerr
- ●Frost dates read at Kerr's scale: Apr 26 to Oct 12
YOUR Parcel
- ✓Your exact zone, not Kerr's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Kerr
Pull a site-specific report for your exact address in Kerr, Montana — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Kerr averages can't show:
We read public map data around Kerr — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Kerr average
How we know this about Kerr
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 Kerr’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 Kerr
When does frost risk typically end in Kerr?
The last hard freeze (28°F) in Kerr typically lands around Apr 26, 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 17.
When is the first frost in Kerr?
The first hard freeze (28°F) in Kerr typically arrives around Oct 12, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 28, so the watching starts about Sep 12 — about 169 days after the spring freeze cleared.
How long is the growing season in Kerr?
Measured between 28°F hard freezes, Kerr sees about 169 frost-free days — roughly Apr 26 through Oct 12, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 17 to Sep 28, about 134 days.
Is the soil safe to grow vegetables in Kerr?
The federal record around Kerr is a meaningful one — 127 documented sites, mostly Underground Storage Tanks entries (53), the nearest Nitrate record about 0.9 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 Kerr?
From about Sep 12 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 12 (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 12. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Kerr's scale — its 6a band and its 169-day season. Your yard writes its own version of Kerr'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 Kerr’s own scale
6 of the readings below were taken at Kerr's own scale — its own ~169-day season between 28°F freezes, the 582 acres it covers and 127 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Kerr's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Kerr's own 28°F hard-freeze dates, about Apr 26 and Oct 12 and the ~169-day span between themNOAA 1991–2020 Climate Normals
- 127 documented contamination sites on the federal record near Kerr, the closest Nitrate record about 0.9 miles out from the town centreFederal environmental registers
- Kerr's boundary and the 582 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~169-day seasonGrowable Ground crop-matching engine
- The ecoregion at Kerr's own centroid, the Northern RockiesUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Kerr's 582 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 Montana grower plans around — written at state scale, so they stay on the state guidefrom Montana
- 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 Kerr's 582 acreswhy one lot differs from the next →
- Which side of Kerr you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 582 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate record about 0.9 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 Kerr-wide figureread your own land →
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