Fort Benton, Montana, sits in USDA hardiness zone 4a — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
Among the crops suited to this profile: cabbage, cranberry, turkish rocket, and collard greens. The site-level story — soil, sun, drainage — decides the rest.
Even in Fort Benton, 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 Benton 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 Benton — soil, climate, flood, and parcel records. How we handle your address.
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Fort Benton — the short answer
Fort Benton, Montana: USDA zone 4a, about 154 days between hard freezes, across 1K acres of city.
- USDA zone
- 4a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 2
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 3
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~154
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 1K 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 Benton's average, not your lot's — a low corner or a tree line moves it. Against Fort Benton's 154-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Fort Benton
Each reading below is measured for Fort Benton itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredFort Benton runs about 154 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 Benton 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 Benton is in
Fort Benton sits in the Northwestern Glaciated Plains — EPA Level III, inside the wider Great Plains. That is read at Fort Benton's own centroid rather than borrowed from Chouteau County.
What Grows in Fort Benton
Every plant below cleared Fort Benton's own zone 4a and its 154-day season. Each card opens that plant's Montana profile. How we score.
Is it too late to plant in Fort Benton?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Apr 4; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 2 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 3 — 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 Benton
Closest first, within ~10 miles of Fort Benton. Listing isn't leaking, and distance isn't exposure.
- SCOTTS LUMBER AND SUPPLY CO INCUnderground Storage Tanks · 600 ft
- MONTANA HONEY INCUnderground Storage Tanks · 900 ft
- JIM TAYLOR CHEVROLETBrownfields · 1600 ft
- JIM TAYLOR CHEV OLDS PONT GMC INCUnderground Storage Tanks · 1700 ft
- WILLSON RANCHUnderground Storage Tanks · 1700 ft
- BENJAMIN RANCHUnderground Storage Tanks · 1700 ft
- BASIL R FULTZUnderground Storage Tanks · 1700 ft
- LAZY K SIX RANCH INCUnderground Storage Tanks · 1700 ft
- GARY J GOTTFRIEDUnderground Storage Tanks · 1700 ft
- MICHAEL V OHARA 802253Underground Storage Tanks · 1700 ft
- N HANGING 5 RANCHUnderground Storage Tanks · 1700 ft
- CLINE FARMS INCUnderground Storage Tanks · 1700 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Fort Benton'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 Benton.
Sources Checked
within ~10 miles of Fort Benton
Severity Distribution
within ~10 miles of Fort Benton
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Fort Benton, Underground Storage Tanks runs higher than the national average — 42 sites within ~10 miles of Fort Benton. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Fort Benton
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 Benton average
Your land is one point inside Fort Benton
Everything above resolves to Fort Benton as a whole — one PHZM band and one 28°F frost record, read across 1K 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 Fort Benton Average
Fort Benton Average
- ●USDA Zones 4a, averaged across Fort Benton
- ●One soil character for all of Fort Benton
- ●Frost dates read at Fort Benton's scale: May 2 to Oct 3
YOUR Parcel
- ✓Your exact zone, not Fort Benton's 4a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Fort Benton
Pull a site-specific report for your exact address in Fort Benton, Montana — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Fort Benton averages can't show:
We read public map data around Fort Benton — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Fort Benton average
How we know this about Fort Benton
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 Fort Benton’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 Fort Benton
When does frost risk typically end in Fort Benton?
The last hard freeze (28°F) in Fort Benton typically lands around May 2, 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 23.
When is the first frost in Fort Benton?
The first hard freeze (28°F) in Fort Benton typically arrives around Oct 3, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 19, so the watching starts about Sep 3 — about 154 days after the spring freeze cleared.
How long is the growing season in Fort Benton?
Measured between 28°F hard freezes, Fort Benton sees about 154 frost-free days — roughly May 2 through Oct 3, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 23 to Sep 19, about 119 days.
Is the soil safe to grow vegetables in Fort Benton?
The federal record around Fort Benton shows 54 documented sites, mostly Underground Storage Tanks entries (42), the nearest Underground Storage Tanks record about 0.1 miles out — a typical footprint for a growing area, and proximity to a documented site is information, not a diagnosis of any one yard. It's worth seeing which recorded sites sit closest to where you grow, and testing the soil before new food beds near any of them.
How do I protect my plants from frost in Fort Benton?
From about Sep 3 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 3 (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 3. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Fort Benton's scale — its 4a band and its 154-day season. Your yard writes its own version of Fort Benton'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 Benton’s own scale
6 of the readings below were taken at Fort Benton's own scale — its own ~154-day season between 28°F freezes, the 1,468 acres it covers and 54 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Fort Benton's own USDA hardiness band, zones 4aUSDA PHZM 2023
- Fort Benton's own 28°F hard-freeze dates, about May 2 and Oct 3 and the ~154-day span between themNOAA 1991–2020 Climate Normals
- 54 documented contamination sites on the federal record near Fort Benton, the closest Underground Storage Tanks record about 0.1 miles out from the town centreFederal environmental registers
- Fort Benton's boundary and the 1,468 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4a and a ~154-day seasonGrowable Ground crop-matching engine
- The ecoregion at Fort Benton'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 Benton's 1,468 acres read through its county's SSURGO summaryfrom Chouteau County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Chouteau 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 Chouteau County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Fort Benton's 1,468 acreswhy one lot differs from the next →
- Which side of Fort Benton you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,468 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.1 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 Benton-wide figureread your own land →
More in Montana
Wider growing context
What grows across MontanaFort Benton sits outside our named growing regions, so Montana as a whole is its closest context here.
Nearby growing guides