Fort Belknap Agency, Montana, sits in USDA hardiness zone 4a — a zone band wide enough that plant choice, not possibility, is the interesting question.
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 Fort Belknap Agency, 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 Fort Belknap Agency 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 Fort Belknap Agency — soil, climate, flood, and parcel records. How we handle your address.
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Fort Belknap Agency — the short answer
Fort Belknap Agency, Montana: USDA zone 4a, about 160 days between hard freezes, across 29K acres of town.
- USDA zone
- 4a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 28
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 5
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~160
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 29K 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 Fort Belknap Agency's average, not your lot's — a low corner or a tree line moves it. Against Fort Belknap Agency's 160-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Fort Belknap Agency
Each reading below is measured for Fort Belknap Agency itself — here is what it means for a garden here, and the move an experienced grower makes about it.

Season length
MeasuredFort Belknap Agency 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
MeasuredFort Belknap Agency 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 Fort Belknap Agency is in
Fort Belknap Agency sits in the Northwestern Glaciated Plains — EPA Level III, inside the wider Great Plains. That is read at Fort Belknap Agency's own centroid rather than borrowed from Blaine County.
What Grows in Fort Belknap Agency
Every plant below cleared Fort Belknap Agency's own zone 4a and its 160-day season. Each card opens that plant's Montana profile. How we score.






























Is it too late to plant in Fort Belknap Agency?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Mar 31; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 28 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 5 — long-season crops need about 90 days of runway, quick greens only 30. The tail of the season still works: sixty-day crops into late summer, quick greens after, garlic last of all.
What's on the federal record near Fort Belknap Agency
Closest first, within ~10 miles of Fort Belknap Agency. Listing isn't leaking, and distance isn't exposure.
- BN HARLEM MICROWAVEUnderground Storage Tanks · 2.0 mi
- FORT BELKNAP KWIKSTOPUnderground Storage Tanks · 5.0 mi
- BUREAU OF INDIAN AFFAIRS FACILITYBrownfields · 5.2 mi
- E Z MARTUnderground Storage Tanks · 8.4 mi
- HARLEM AIRPORTUnderground Storage Tanks · 8.5 mi
- NORTH HARLEM COLONYUnderground Storage Tanks · 8.5 mi
- BN HARLEM SECTION TOOL HOUSEUnderground Storage Tanks · 8.5 mi
- PHS INDIAN HOSPITALUnderground Storage Tanks · 8.5 mi
- BAKERS SERVICE CENTER INCUnderground Storage Tanks · 8.5 mi
- HARLEM SHOPUnderground Storage Tanks · 8.5 mi
- FRED O DOLVENUnderground Storage Tanks · 8.6 mi
- EQUITY COOP ASSOCIATION CENTRAL AVE WUnderground Storage Tanks · 8.6 mi
1 more site is on the record inside the same radius. See them on the map
Measured from Fort Belknap Agency'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 Fort Belknap Agency.
Severity Distribution
within ~10 miles of Fort Belknap Agency
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.
Check your specific parcel in Fort Belknap Agency
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 Fort Belknap Agency average
Your land is one point inside Fort Belknap Agency
Everything above resolves to Fort Belknap Agency as a whole — one PHZM band and one 28°F frost record, read across 29K 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 Fort Belknap Agency Average
Fort Belknap Agency Average
- ●USDA Zones 4a, averaged across Fort Belknap Agency
- ●One soil character for all of Fort Belknap Agency
- ●Frost dates read at Fort Belknap Agency's scale: Apr 28 to Oct 5
YOUR Parcel
- ✓Your exact zone, not Fort Belknap Agency's 4a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Fort Belknap Agency
Pull a site-specific report for your exact address in Fort Belknap Agency, Montana — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Fort Belknap Agency averages can't show:
We read public map data around Fort Belknap Agency — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Fort Belknap Agency average
How we know this about Fort Belknap Agency
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 Fort Belknap Agency’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 Fort Belknap Agency
When does frost risk typically end in Fort Belknap Agency?
The last hard freeze (28°F) in Fort Belknap Agency typically lands around Apr 28, 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 19.
When is the first frost in Fort Belknap Agency?
The first hard freeze (28°F) in Fort Belknap Agency typically arrives around Oct 5, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 21, so the watching starts about Sep 5 — about 160 days after the spring freeze cleared.
How long is the growing season in Fort Belknap Agency?
Measured between 28°F hard freezes, Fort Belknap Agency sees about 160 frost-free days — roughly Apr 28 through Oct 5, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 19 to Sep 21, about 125 days.
Is the soil safe to grow vegetables in Fort Belknap Agency?
The federal record around Fort Belknap Agency is light — 13 documented sites across the 9 federal source types we checked, mostly Underground Storage Tanks entries (12), the nearest Underground Storage Tanks record about 2.0 miles out — and proximity to a documented site is information, not a diagnosis of any one yard. Growing food here starts from a strong position; a soil test before new food beds settles any site-specific question.
How do I protect my plants from frost in Fort Belknap Agency?
From about Sep 5 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 5 (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 5. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Fort Belknap Agency's scale — its 4a band and its 160-day season. Your yard writes its own version of Fort Belknap Agency'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 Fort Belknap Agency’s own scale
6 of the readings below were taken at Fort Belknap Agency's own scale — its own ~160-day season between 28°F freezes, the 29,122 acres it covers and 13 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Fort Belknap Agency's own USDA hardiness band, zones 4aUSDA PHZM 2023
- Fort Belknap Agency's own 28°F hard-freeze dates, about Apr 28 and Oct 5 and the ~160-day span between themNOAA 1991–2020 Climate Normals
- 13 documented contamination sites on the federal record near Fort Belknap Agency, the closest Underground Storage Tanks record about 2.0 miles out from the town centreFederal environmental registers
- Fort Belknap Agency's boundary and the 29,122 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 Fort Belknap Agency's own centroid, the Northwestern Glaciated PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Fort Belknap Agency's 29,122 acres read through its county's SSURGO summaryfrom Blaine County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Blaine 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 Blaine County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Fort Belknap Agency's 29,122 acreswhy one lot differs from the next →
- Which side of Fort Belknap Agency you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 29,122 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 2.0 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 Fort Belknap Agency-wide figureread your own land →
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