Missoula County, in Montana, sits in USDA hardiness zone 5b — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
The conditions favor cabbage, cranberry, lavender, and collard greens, among others — though every individual site edits that list with its own soil, sun, and drainage.
Missoula County lies within the Bitterroot Valley — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Missoula County holds more than one microclimate.
Soils and elevations shift across Missoula County, so your frost dates and drainage aren't the county average. 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 Missoula County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Missoula County — the short answer
Missoula County, Montana: USDA zone 5b, about 137 days between hard freezes, across 1.7M acres.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 16
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Sep 30
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~137
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 1.7M acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are county 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 5b is Missoula County's average, not your lot's — a low corner or a tree line moves it. Against Missoula County's 137-day season, see what your own ground reads.
Heat in Missoula County
Across a year, Missoula County accumulates about 757 growing degree days above 50°F, about 913 fewer than the middle Montana county — ahead of 5 of Montana’s 56 counties. Degree days are the heat a crop actually gets to work with — more of them is more room to ripen a long-season crop before the freeze closes the window.
Grounded in PRISM Climate Group, Oregon State University — 1991–2020 monthly normals
Soil in Missoula County
Across Missoula County, the ground is predominantly Inceptisols, where Winkler, Holloway, and Waldbillig are the most extensive named soil series. The soil is generally well drained with a gravelly loam surface. Topsoil pH runs about 5.8–6.7, slightly acidic. Rainfall drains through hydrologic group B soils.
Soil order
Inceptisols
Drainage
Well drained
Prime farmland
1%
Hydric soils
2%
Soil still varies lot by lot — soil types explained.
How the ground varies across Missoula County
The USDA soil survey maps 51% of Missoula County as well drained — but another 39% drains differently: 33% somewhat excessively drained, 3% excessively drained.
Winkler is the most extensive named soil at 14% of mapped acres, then Holloway (8%) and Waldbillig (7%).
Which of them your own lot sits on is a parcel question, not a county one. Check your address for the survey at your boundary.
What this means for growing in Missoula County
Each reading below is measured for Missoula County itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Drainage
MeasuredThe dominant soils across Missoula County are well drained, in hydrologic group B — ground that drains quickly.
The upside is soil you can work early in spring and roots that never drown; the cost is that fast-draining ground dries out fast and leaches nutrients away before plants can use them.
Work in compost and mulch to hold moisture and feed, and water more often in short doses than deep and rarely.
USDA NRCS SSURGO
Surface pH
MeasuredTopsoil across Missoula County runs about pH 5.8–6.7, close to neutral.
This is the range most vegetables prefer — one correction you probably do not have to make, which is genuinely good news for a new bed.
Keep it there with compost rather than lime or sulfur, and only amend if your own soil test says otherwise.
USDA NRCS SSURGO
Season length
MeasuredMissoula County runs about 137 days between hard freezes — a short growing season.
Long-maturing crops like melons, sweet potatoes, and winter squash can run out of runway before the first hard freeze, ripening late or not at all.
Lead with fast-maturing varieties, and stretch the season on both ends with cold frames, low tunnels, or a greenhouse.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredMissoula County sits in USDA hardiness zone 5b.
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 Missoula County is in
Missoula County spans 3 EPA Level III ecoregions — Middle Rockies (52%), Northern Rockies (30%) and Canadian Rockies (16%). Which one your land falls in changes what grows wild there and how the ground behaves, and a county-wide answer cannot tell you which.
What Grows in Missoula County
We scored all 1,086 plants against Missoula County's own USDA zone 5b and its own 137-day season between hard freezes, using the same matching engine that runs a full parcel report. These cleared both. Sun, soil pH and drainage vary lot by lot — those are the parcel questions below. Each card opens that plant's Montana profile.
Is it too late to plant in Missoula County?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Apr 18; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 16 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Sep 30 — long-season crops need about 90 days of runway, quick greens only 30. When the window is tight, the fall moves are quick ones — baby greens, radishes, and garlic set for next season.
Documented around Missoula County
- monarch butterfly2 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Missoula County
USGS estimates 2,660 lb of Glyphosate on Missoula County farmland in 2019, its largest by weight, ahead of 2,4-d (1,344 lb) and Bromoxynil (438 lb).
Farmland across the whole county, not any one lot. Check your address for the site-by-site record.
Safe to Grow Here?
What the federal record shows across Missoula County — and how to grow with it.
We checked the federal record across Missoula County — 829 documented sites across 8 of the 9 source types we track.
The most significant on record: 8 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Missoula 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.
What's on the federal record near Missoula County
Closest first, across Missoula County. Listing isn't leaking, and distance isn't exposure.
- Bonanza Lime ProspectMining · 4.4 mi
- Copper ProspectMining · 4.5 mi
- Looks Grim ProspectMining · 4.9 mi
- HollidayMining · 6.5 mi
- Holiday ClaimMining · 6.6 mi
- Juniper ProspectMining · 7.7 mi
- 15N20W13DCAA01Nitrate · 8.4 mi
- 15N19W07BCCC01Nitrate · 8.5 mi
- BIG PINES TRAILER COURTPFAS · 8.6 mi
- GRAY WOLF PEAKUnderground Storage Tanks · 8.8 mi
- 15N20W13BABB01Nitrate · 9.0 mi
- 15N20W23DCAA01Nitrate · 9.2 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Missoula County'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 Missoula County.
Severity Distribution
across Missoula County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Missoula County, Mining runs higher than the national average — 121 sites across Missoula County. 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 Missoula County
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 Missoula County average
Your land is one point inside Missoula County
Everything above resolves to Missoula County as a whole — one PHZM band and one county frost record, read across 1.7M 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 county 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 county average.
Your Lot vs the Missoula County Average
Missoula County Average
- ●USDA Zones 5b, averaged across Missoula County
- ●One soil character for all of Missoula County
- ●Frost dates read at Missoula County's scale: May 16 to Sep 30
YOUR Parcel
- ✓Your exact zone, not Missoula County's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Missoula County
Pull a site-specific report for your exact address in Missoula County, Montana — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Missoula County averages can't show:
We read public map data around Missoula County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Missoula County average
How we know this about Missoula County
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at county grain; hard-freeze dates from NOAA 1991–2020 28°F normals at this county’s own record where one resolves, and the labelled statewide window where none does; soils from the USDA NRCS SSURGO survey, area-weighted across the county’s own map units; boundaries and acreage from US Census TIGER/Line 2025; the contamination and pesticide records from the federal sources named in their beats above. Where Missoula County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Missoula County
When does frost risk typically end in Missoula County?
The last hard freeze (28°F) in Missoula County typically lands around May 16, 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 Jun 6.
How long is the growing season in Missoula County?
Measured between 28°F hard freezes, Missoula County sees about 137 frost-free days — roughly May 16 through Sep 30, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 6 to Sep 16, about 102 days.
Is the soil safe to grow vegetables in Missoula County?
The federal record around Missoula County runs heavier than most — 829 documented sites, mostly Underground Storage Tanks entries (402), the nearest Mining record about 4.4 miles out — 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.
How do gardeners stretch the season in Missoula County?
With about 137 frost-free days between hard freezes, Missoula County rewards the classic extension moves: floating row cover buys roughly two to four extra weeks at each shoulder — on this season that is a working window nearer 165 to 193 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 16 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Missoula County's scale — its 5b band and its 137-day season. Your yard writes its own version of Missoula County's numbers: 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.
What this page reads at Missoula County’s own scale
9 of the readings below were taken at Missoula County's own scale — its own ~137-day span between 28°F freezes, the 3 most extensive soil series mapped here and 829 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Missoula County's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Missoula County's own 28°F hard-freeze dates and its ~137-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Missoula CountyUSDA NRCS SSURGO
- 829 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Mining record about 4.4 miles outFederal environmental registers
- Missoula County's boundary and the 1,659,525 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~137-day seasonGrowable Ground crop-matching engine
- The 3 ecoregions Missoula County spans, Middle Rockies the largestUS EPA Level III Ecoregions
- Open occurrence records documented in Missoula County for a tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Missoula County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every Montana grower plans around — written at state scale, so they stay on the state guidefrom Montana
What this page can’t tell you
- How the season shifts across Missoula County — the ~137 days above is one reading at its centre; the 12 towns below each carry their owntowns in this county →
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Missoula County's 1,659,525 acreswhy one lot differs from the next →
- Which of those 829 documented sites actually reaches your soil — that needs your address, the wind, and the groundwater directionhow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — none of it survives being averaged over Missoula Countyread your own land →