Ravalli County, in Montana, sits in USDA hardiness zone 6a — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
Growers here do well with cabbage, blackberry, california poppy, and collard greens — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Ravalli 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
Ravalli County holds more than one microclimate.
Soils and elevations shift across Ravalli 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 Ravalli County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Ravalli County — the short answer
Ravalli County, Montana: USDA zone 6a, about 146 days between hard freezes, across 1.5M acres.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 6
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Sep 29
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~146
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 1.5M 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 6a is Ravalli County's average, not your lot's — a low corner or a tree line moves it. Against Ravalli County's 146-day season, see what your own ground reads.
Heat in Ravalli County
Across a year, Ravalli County accumulates about 1,140 growing degree days above 50°F, about 530 fewer than the middle Montana county — ahead of 18 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 Ravalli County
Across Ravalli County, the ground is predominantly Inceptisols, where Chereete, Riverrun, and Farnuf are the most extensive named soil series. The soil is generally well drained with a gravelly sandy loam surface. Topsoil pH runs about 5.3–6.5, moderately acidic. Rainfall drains through hydrologic group A soils.
Soil order
Inceptisols
Drainage
Well drained
Hydric soils
4%
Soil still varies lot by lot — soil types explained.
How the ground varies across Ravalli County
The USDA soil survey maps 58% of Ravalli County as well drained — but another 31% drains differently: 22% excessively drained, 3% somewhat excessively drained.
Chereete is the most extensive named soil at 2% of mapped acres, then Riverrun (1%) and Farnuf (1%).
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 Ravalli County
Each reading below is measured for Ravalli 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 Ravalli County are well drained, in hydrologic group A — 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 Ravalli County runs about pH 5.3–6.5, on the acidic side.
Blueberries, potatoes, and rhododendrons thrive in it, but most vegetables start locking out nutrients below about pH 6.0 and grow pale and stunted no matter how much you feed them.
A measured lime application raises pH for the crops that need it — but test first, because the right rate depends on your own soil, not the county average.
USDA NRCS SSURGO
Season length
MeasuredRavalli County runs about 146 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
MeasuredRavalli County sits in USDA hardiness zone 6a.
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 Ravalli County is in
Ravalli County spans 2 EPA Level III ecoregions — Idaho Batholith (67%) and Middle Rockies (33%). 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 Ravalli County
We scored all 1,086 plants against Ravalli County's own USDA zone 6a and its own 146-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 Ravalli 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 Sep 29 — long-season crops need about 90 days of runway, quick greens only 30. Short seasons reward decisiveness — quick-maturing varieties late, hardy greens under cover, and next year’s garlic in the ground before it closes.
What gets applied to farmland in Ravalli County
USGS estimates 5,337 lb of Glyphosate on Ravalli County farmland in 2019, its largest by weight, ahead of 2,4-d (1,200 lb) and Metolachlor-s (941 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 Ravalli County — and how to grow with it.
We checked the federal record across Ravalli County — 783 documented sites across 8 of the 9 source types we track.
The most significant on record: 1 Superfund site (none NPL-listed). Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
There's a meaningful federal record across Ravalli County — worth a look before you plant food, not a reason to hold back from growing. Proximity to a documented site is information, not a diagnosis of any one yard. A soil test before new food beds is the sensible precaution here, and the map shows exactly which sites sit where, so you can see what's actually near you.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Ravalli County
Closest first, across Ravalli County. Listing isn't leaking, and distance isn't exposure.
- Slate Creek MineMining · 0.8 mi
- A B CONCRETE INCUnderground Storage Tanks · 3.4 mi
- 04N21W14CBAA01Nitrate · 3.8 mi
- 04N21W35CCBA01Nitrate · 3.9 mi
- MDOT HAMILTON SITEUnderground Storage Tanks · 4.0 mi
- PORTERBILT CO INCUnderground Storage Tanks · 4.3 mi
- S & W SAWMILL FACILITYBrownfields · 4.7 mi
- DARBY LUMBERUnderground Storage Tanks · 4.7 mi
- 04N21W16DDDD01Nitrate · 4.8 mi
- ROCKY MOUNTAIN LOG HOMESUnderground Storage Tanks · 4.8 mi
- DARBY RANGER STATIONUnderground Storage Tanks · 4.9 mi
- 05N21W36DCC 02Nitrate · 5.1 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Ravalli 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 Ravalli County.
Total Sites
783
across Ravalli County
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Severity Distribution
across Ravalli County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Ravalli County, two things run higher than the national average across Ravalli County — Nitrate (588 sites) and Mining (51 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
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 well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Check your specific parcel in Ravalli 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 Ravalli County average
Your land is one point inside Ravalli County
Everything above resolves to Ravalli County as a whole — one PHZM band and one county frost record, read across 1.5M 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 Ravalli County Average
Ravalli County Average
- ●USDA Zones 6a, averaged across Ravalli County
- ●One soil character for all of Ravalli County
- ●Frost dates read at Ravalli County's scale: May 6 to Sep 29
YOUR Parcel
- ✓Your exact zone, not Ravalli County's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Ravalli County
Pull a site-specific report for your exact address in Ravalli County, Montana — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Ravalli County averages can't show:
We read public map data around Ravalli County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Ravalli County average
How we know this about Ravalli 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 Ravalli County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Ravalli County
When does frost risk typically end in Ravalli County?
The last hard freeze (28°F) in Ravalli County typically lands around May 6, 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 27.
How long is the growing season in Ravalli County?
Measured between 28°F hard freezes, Ravalli County sees about 146 frost-free days — roughly May 6 through Sep 29, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 27 to Sep 15, about 111 days.
Is the soil safe to grow vegetables in Ravalli County?
The federal record around Ravalli County is a meaningful one — 783 documented sites, mostly Nitrate entries (588), the nearest Mining record about 0.8 miles out — so a soil test before new food beds is a sensible precaution here, not a reason to hold back from growing. Remember that proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what sits where.
How do gardeners stretch the season in Ravalli County?
With about 146 frost-free days between hard freezes, Ravalli 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 174 to 202 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 6 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Ravalli County's scale — its 6a band and its 146-day season. Your yard writes its own version of Ravalli 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 Ravalli County’s own scale
8 of the readings below were taken at Ravalli County's own scale — its own ~146-day span between 28°F freezes, the 3 most extensive soil series mapped here and 783 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Ravalli County's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Ravalli County's own 28°F hard-freeze dates and its ~146-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Ravalli CountyUSDA NRCS SSURGO
- 783 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Mining record about 0.8 miles outFederal environmental registers
- Ravalli County's boundary and the 1,530,217 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~146-day seasonGrowable Ground crop-matching engine
- The 2 ecoregions Ravalli County spans, Idaho Batholith the largestUS EPA Level III Ecoregions
- Which agricultural compounds go onto Ravalli 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 Ravalli County — the ~146 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 Ravalli County's 1,530,217 acreswhy one lot differs from the next →
- Which of those 783 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 Ravalli Countyread your own land →