Beaverhead County, in Montana, sits in USDA hardiness zone 5a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
Growers here do well with cherry, potato, lentil, and ponderosa pine — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Beaverhead County holds more than one microclimate.
Soils and elevations shift across Beaverhead County, so your frost dates and drainage aren't the county average. Enter your address and we'll score 1,112 plants against your land's actual soil, sun, and frost.
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
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Quick Facts
USDA Zones
5a
Last Hard Freeze (28°F)
May 6
County normal — light frosts run a few weeks later
First Hard Freeze (28°F)
Oct 10
County normal — light frosts arrive a few weeks earlier
County Area
3.5M acres
Hardiness Zone Range
Zone maps are averages across Beaverhead County. Your yard's slope, trees, and frost pockets shift what actually grows — see your land's exact reading.
Soil in Beaverhead County
Across Beaverhead County, the ground is predominantly Mollisols, where Philipsburg, Maciver, and Bronec are the most extensive named soil series. The soil is generally well drained with a gravelly loam surface. Topsoil pH runs about 6.1–7.2, neutral. Rainfall drains through hydrologic group B soils.
Soil order
Mollisols
Drainage
Well drained
Hydric soils
6%
Soil still varies lot by lot — soil types explained.
What Grows in Beaverhead County
Plants matched to Beaverhead County's USDA zones 5a — each links to its full growing profile.
Is it too late to plant in Beaverhead County?
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 8; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 6 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 10 — 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.
Growing Challenges in Montana
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 Beaverhead County — and how to grow with it.
We checked the federal record across Beaverhead County — 716 documented sites across 8 of the 9 source types we track.
The most significant on record: 3 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Beaverhead County 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.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
Environmental Intelligence
Understanding what's nearby helps you make informed decisions about where and how to grow.
Sources Checked
across Beaverhead County
Severity Distribution
across Beaverhead County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Beaverhead County, Mining runs higher than the national average — 444 sites nearby. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Mining: Mining sites — both historic and active — can leach heavy metals (arsenic, lead, cadmium, mercury) into soil and water for centuries after operations cease.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Check your specific parcel in Beaverhead County
Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,112 plant recommendations.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources analyzed in seconds
Your Specific Parcel Matters
Beaverhead County Average
- ●USDA Zones 5a
- ●Generic soil type for the area
- ●State-average frost dates
YOUR Parcel
- ✓Your exact hardiness zone
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Beaverhead County
Pull a site-specific report for your exact address in Beaverhead County, Montana — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources analyzed in seconds
Key Growing Facts for Beaverhead County, Montana
- USDA Hardiness Zones: 5a (USDA PHZM 2023)
- Last Hard Freeze (28°F): May 6 (county normal, NOAA 1991–2020 Climate Normals — light frosts can follow for a few weeks)
- First Hard Freeze (28°F): Oct 10 (county normal, NOAA 1991–2020 Climate Normals — light frosts can arrive a few weeks earlier)
- Days Between Hard Freezes: ~157 (county normal, NOAA 1991–2020 Climate Normals)
- County Land Area: 3.5M acres (US Census TIGER 2025)
Zone data: USDA ARS Plant Hardiness Zone Map 2023. Climate data: NOAA NCEI. County boundaries: US Census TIGER/Line 2025.
Frost dates here are the Beaverhead County average. Low spots and tree cover move them by days on any one yard — see your exact frost windows.
Frequently Asked Questions
What hardiness zone is Beaverhead County, Montana?
Beaverhead County sits in USDA hardiness zone 5a, per the USDA Plant Hardiness Zone Map 2023. Zones reflect average annual extreme minimum temperatures from 1991–2020 weather data.
Is it too late to plant in Beaverhead County?
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 8; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 6 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 10 — 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.
When does frost risk typically end in Beaverhead County?
The last hard freeze (28°F) in Beaverhead County typically lands around May 6, per NOAA 1991–2020 climate normals — an earlier marker than the light-frost dates many planting charts quote. That marks the hard freeze, not the last light frost — light frosts can still bite for a few more weeks, so tender transplants usually wait another 2–3 weeks.
How long is the growing season in Beaverhead County?
Measured between 28°F hard freezes, Beaverhead County sees about 157 frost-free days — roughly May 6 through Oct 10, per 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.
What vegetables grow in Beaverhead County?
Beaverhead County's zone 5a supports 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.
Which hardiness zone is Beaverhead County, really?
Officially, Beaverhead County sits in USDA zone 5a (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 1,112 plants against what's actually there.
Is the soil safe to grow vegetables in Beaverhead County?
The federal record around Beaverhead County runs heavier than most — 716 documented sites — 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.
Just moved to Beaverhead County — what should I know before planting?
Start with three facts. Beaverhead County sits in USDA zone 5a, which sets what survives winter; the last 28°F hard freeze typically clears around May 6, with about 157 frost-free days to work with (NOAA 1991–2020 climate normals); and 716 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 on this page is a Beaverhead County average. Your yard writes its own version — we read soil, sun, drainage, and frost at your exact address. Try it for 14 days — no card required.
Will It Grow Here?
Zone fit is the first question — each answer below reads Montana's frost window, season length, and soil profile against the plant's real requirements.