Montana spans USDA hardiness zones 3a-6b, with a growing season of about 151 frost-free days — enough room for the full run of cool-season vegetables plus warm-season crops that finish before the first hard frost.
The climate hand here is 10-20 inches of annual rainfall, a median of roughly 1,769 growing-degree days (base 50°F), and about 2,500 winter chill hours for tree fruit — the numbers that decide what ripens comfortably and what runs out of runway. The soil story is sandy loam, clay, glacial till, and volcanic ash — and reading their drainage is half the battle of siting any planting. Growing in Montana really means growing in one of its distinct regions — The Hi-Line, The Yellowstone Valley, and The Rocky Mountain Front / Great Falls Chinook Belt — each with its own zone band and frost rhythm. On paper, cherry, potato, lentil, and ponderosa pine all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Grounded inUSDA PHZM•NOAA Climate Normals•USDA NRCS SSURGO•GDD (PRISM 1991-2020 normals)•Chill hours (PRISM 1991-2020 normals)•USDA hardiness sub-region map•EPA FRS•USDA PLANTS•Growable Ground suitability scoring
Montana spans zones 3a-6b, but your yard sits in exactly one — and slope, tree cover, and low spots nudge it further. 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 Montana — soil, climate, flood, and parcel records. How we handle your address.
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Distinct growing regions within Montana — each has its own zones, soils, and signature crops.
Montana: USDA zones 3a-6b, 59–170 frost-free days depending on the county, 56 counties.
The middle half of this state’s counties. Tender transplants usually wait 2–3 weeks past the last hard freeze. The shortest-season figure is Montana's own county record — Deer Lodge County's measured 28°F normal, not a modeled floor.
Montana does not have one growing season. Across all 490 of its towns that carry their own 30-year record, the shortest measured season is Wisdom's at 51 days and the longest is St. Ignatius's at 174 — a 123-day spread inside one state.
Neither end is a lone reading — one other town measures within 10 days of Wisdom and 62 sit within 10 days of St. Ignatius. These are real pockets, so the number to plant against is your own town's, not the state average.
NOAA Regional Climate Centers ACIS (1991–2020), 30-year daily minimum record
Zone 3a-6b is Montana's average, not your lot's — a low corner or a tree line moves it. Against Montana's 151-day season, see what your own ground reads.
One answer for Montana averages 56 counties whose growing seasons are 111 days apart — from 59 frost-free days in Deer Lodge County to 170 in Petroleum County. That is the same state, measured the same way, in the same years. Which end of it your county sits nearer decides what finishes before the first hard freeze.
The middle half of 56 counties runs 137–158 days, with a median of 150 days — a 111-day span end to end.
Measured across 56 counties, each carrying its own 28°F normal. NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze. A county with no record of its own is absent from the range rather than counted as zero — nothing here is interpolated to the state. Your own site sits somewhere inside this range; a parcel report resolves where.
The middle half of Montana runs 137–158 frost-free days, and 26 of its 56 counties sit outside that — 13 on the short side, 13 on the long. A statewide planting date describes the middle well and the ends poorly, which is worth knowing before you follow one.
Under 137 frost-free days
13 counties
3 of 13 shown
The end of the state that sets the planting calendar — start seed indoors here and the season stretches to meet the crop.
137–158 frost-free days
30 counties
0 of 30 shown
The middle half of the state, and the part a single statewide date describes well.
Over 158 frost-free days
13 counties
3 of 13 shown
Long enough for a second succession of a quick crop after the first comes out.
Each county is placed by its own 28°F frost-free normal (NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze), the same figure its own guide page publishes. Elevation, slope and cold-air drainage move a yard within its county as well — which is the part only your address resolves.
The soil types that dominate Montana — how each drains decides more about crop success than almost anything else. Tap any soil to learn what it is and how to work with it. Each photo is a representative profile of that soil type; the named series is where it was documented, which is often another state.
Drainage
Fast. The sand fraction opens the soil up, so water moves through the root zone quickly and the surface rarely stays soggy. The trade is that nutrients ride out with the water.
What thrives
Root crops love it — carrots, potatoes, radishes, and onions size up cleanly in ground they can push through. Melons, sweet potatoes, asparagus, and most herbs appreciate the warmth and the drainage.
Drainage
Slow. Water enters clay reluctantly and leaves it the same way, so wet springs keep it cold and unworkable longer than lighter soils.
What thrives
Once established, heavy feeders prosper — brassicas, beans, corn, and many fruit trees ride clay’s nutrient supply and summer moisture reserve. Daylilies, roses, and prairie perennials handle it without complaint.
Drainage
Variable by the shovelful. Sandy till drains freely; dense, compacted till (hardpan) can perch water above it after snowmelt and heavy rain.
What thrives
Apples, stone fruits, brambles, and the whole northern vegetable garden do well on till — much of New England and the upper Midwest farms it. Deep-rooted perennials work through the stony structure happily.
Drainage
Excellent and unusual: ash soils drain freely yet hold remarkable amounts of plant-available water in their porous structure — the best of both habits.
What thrives
Volcanic regions grow celebrated crops the world over: orchards, berries, vegetables, coffee, and wine grapes all prosper on ash-derived soils.
Soil data: USDA NRCS SSURGO · Soil types explained
Plants well-suited to Montana's climate, soils, and growing season — each links to its full growing profile.
Usually not — gardeners here simply switch what goes in the ground as the season moves. Across Montana, cool-season planting typically opens about four weeks before the local last hard freeze — county medians put that freeze near May 5, with the middle half of counties between May 2 and May 13 (NOAA 1991–2020 climate normals). Tender transplants wait two to three weeks past it, and fall planting counts back from first freezes mostly between Sep 28 and Oct 7 — 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.
The plants Montana put its name on — cultural emblems, not growing recommendations.
Bitterroot
Lewisia rediviva
Designated 1894.
Pinus ponderosa
Designated 1949. In our plant library — see its full growing profile.
Designated 2023. In our plant library — see its full growing profile.
Plants the USDA PLANTS Database documents as native and present in Montana — a real per-state range, not just a zone match. Ordered by how closely each plant’s published hardiness range matches Montana’s zones 3a-6b, so this is a shortlist by climate fit, not a ranking of which plants matter most here. Presence is statewide, so a plant may still be uncommon in your specific county; your state’s Cooperative Extension or a native-plant society is the local authority.
US-native plants whose hardiness range overlaps Montana’s USDA zones 3a-6b but which USDA PLANTS doesn’t map to a single state range here. Zone overlap is a starting filter, not a range map.
What an experienced grower plans around here — each one has a move.
Very short growing season (60-100 frost-free days)
At 60-100 frost-free days, a high tunnel or cold frame isn't a luxury — it's the difference-maker Montana growers rely on.
Low rainfall requires irrigation in most areas
Drip irrigation plus mulch stretches scarce water a long way — plan the system before the first seed.
Extreme winter cold (-40F possible)
Choose perennials rated for the cold you actually get — a -40°F winter audits every optimistic zone push.
For cultivar selection, pest pressure, and planting-time guidance specific to Montana, the Montana State University Extension is the authoritative local source.
Safe to Grow Here?What the federal record shows across Montana — and how to grow with it.
We checked the federal record across Montana — 22,453 documented sites across 8 of the 9 source types we track.
The most significant on record: 124 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Montana carries one of the heavier federal records we track — and that's not a verdict on your yard. Proximity to a documented site is information, not a diagnosis: nothing here says any particular parcel is affected. It does earn one concrete step — before food beds go in the ground, a professional soil test tells you exactly what you're working with, and raised beds with clean imported soil grow well almost anywhere in the meantime.
Severity Distribution
across Montana
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Montana, two things run higher than the national average across Montana — Mining (4,319 sites) and Nitrate (10,260 sites). That's not a problem with your land — it's information about it.
Mining: Mining sites — both historic and active — can leach heavy metals (arsenic, lead, cadmium, mercury) into soil and water for centuries after operations cease.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
Everything above resolves to Montana as a whole — a state whose own counties record seasons 111 days apart, and hardiness across zones 3a-6b. Your parcel sits at one point in that range, not in the middle of it. 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 state 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 statewide average.
State averages sketch the shape. Your soil, sun exposure, drainage, and microclimate decide what actually takes. Pull a site-specific report for your exact parcel.
Enter your address. We read your soil, sun, drainage, and frost dates, then score 1,086 plants against the real conditions on your land.
Three things about your lot that Montana averages can't show:
We read public map data around Montana — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Montana average
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read per county and aggregated to the state band; the growing season from NOAA Regional Climate Centers ACIS 1991–2020 28°F normals, read at each county’s own record; rainfall from NOAA Climate Normals; soils from USDA NRCS SSURGO; boundaries from US Census TIGER/Line 2025; the contamination record from the federal sources named in that beat above. Where a county carries no record of its own, it is absent from the figure rather than filled in.
Montana spans USDA hardiness zones 3a-6b — which is to say winter's coldest night runs from about −40°F to 0°F depending where in Montana you are, averaged over 1991–2020 (USDA PHZM 2023).
Usually not — gardeners here simply switch what goes in the ground as the season moves. Across Montana, cool-season planting typically opens about four weeks before the local last hard freeze — county medians put that freeze near May 5, with the middle half of counties between May 2 and May 13 (NOAA 1991–2020 climate normals). Tender transplants wait two to three weeks past it, and fall planting counts back from first freezes mostly between Sep 28 and Oct 7 — 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.
Across Montana, the middle half of counties see their last hard freeze (28°F) between about May 2 and May 13, with a county median near May 5 (NOAA 1991–2020 climate normals). 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 26.
Measured between 28°F hard freezes, growing seasons across Montana's counties mostly run about 139 to 158 days, with a county median near 151 (NOAA 1991–2020 climate normals). Tender crops get a somewhat shorter practical window, since lighter frosts reach a few weeks past the hard-freeze dates on both ends.
Montana's zones 3a-6b support a wide range — strong performers include Cherry, Potato, Lentil, Ponderosa Pine, and Rhubarb. What actually takes on any one site comes down to its soil, sun, and drainage, and we score each plant against the real conditions at your address.
Officially, Montana spans USDA zones 3a-6b (USDA PHZM 2023) — but a zone is a 30-year average of winter's coldest night across an area, and it can't see any one yard. A south-facing slope, a tree line, or a low frost pocket can shift a single site by half a zone either way, which is why neighboring gardeners often quote different numbers. We read the conditions at your exact address — soil, sun, slope, and frost — and score 1,086 plants against what's actually there.
The federal record across Montana runs heavier than most — 22,453 documented sites, mostly Nitrate entries (10,260) — so test the soil before planting food in the ground, and raised beds with clean imported soil grow well in the meantime. Even here, proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what's recorded and where.
Start with three facts. Montana spans USDA zones 3a-6b, which sets what survives winter; last hard freezes range from about May 2 to May 13 across its counties (NOAA 1991–2020 climate normals); and 22,453 documented sites sit on the federal record here, so a soil test before food beds is the smart first step. From there, matching plants to your actual soil and sun is the fun part.
Everything above is measured at Montana's scale — its 3a-6b band and its 151-day season. Your yard writes its own version of Montana's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
6 of the readings below were taken at Montana's own scale — the full zone 3a-6b span inside its borders, the 4 soil types that dominate its ground and 22,453 documented sites on its federal record; anything it cannot resolve at this scale is named below.
Measured here
What this page can’t tell you
Explore growing conditions by county — each has its own zone range and land area.
Explore growing conditions by city or town in Montana.
