Mineral 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.
Reliable performers under these conditions include cabbage, blackberry, california poppy, and collard greens; what your own ground favors still comes down to its soil, sun, and drainage.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Mineral County holds more than one microclimate.
Soils and elevations shift across Mineral 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 Mineral County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Mineral County — the short answer
Mineral County, Montana: USDA zone 6a, about 150 days between hard freezes, across 781K acres.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 10
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 7
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~150
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 781K 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 Mineral County's average, not your lot's — a low corner or a tree line moves it. Against Mineral County's 150-day season, see what your own ground reads.
Heat in Mineral County
Across a year, Mineral County accumulates about 940 growing degree days above 50°F, about 730 fewer than the middle Montana county — ahead of 12 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 Mineral County
Across Mineral County, the ground is predominantly Inceptisols, where Krause, Half Moon, and Entente are the most extensive named soil series. The soil is generally well drained with a ashy silt loam surface. Topsoil pH runs about 5.8–6.2, moderately acidic. Rainfall drains through hydrologic group B soils.
Soil order
Inceptisols
Drainage
Well drained
Prime farmland
1%
Hydric soils
1%
Soil still varies lot by lot — soil types explained.
How the ground varies across Mineral County
The USDA soil survey maps 89% of Mineral County as well drained — but another 9% drains differently: 4% somewhat excessively drained, 2% somewhat poorly drained.
Krause is the most extensive named soil at 1% of mapped acres, then Half Moon (1%) and Entente (0%).
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 Mineral County
Each reading below is measured for Mineral 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 Mineral 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 Mineral County runs about pH 5.8–6.2, 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
MeasuredMineral County runs about 150 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
MeasuredMineral 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 Mineral County is in
Mineral County sits in the Northern Rockies — EPA Level III, inside the wider Northwestern Forested Mountains. One consistent ecological setting across the whole county.
What Grows in Mineral County
We scored all 1,086 plants against Mineral County's own USDA zone 6a and its own 150-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 Mineral County?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Apr 12; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 10 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 7 — long-season crops need about 90 days of runway, quick greens only 30. Even past midsummer there is room for a true fall garden here, and garlic planted near the close carries the momentum into next year.
What gets applied to farmland in Mineral County
USGS estimates 1,474 lb of Glyphosate on Mineral County farmland in 2019, its largest by weight, ahead of 2,4-d (631 lb) and Atrazine (250 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 Mineral County — and how to grow with it.
We checked the federal record across Mineral County — 203 documented sites across 5 of the 9 source types we track.
The most significant on record: 2 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Mineral 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 Mineral County
Closest first, across Mineral County. Listing isn't leaking, and distance isn't exposure.
- Freezeout Pass MineMining · 2.3 mi
- Amador MineMining · 3.7 mi
- Redemption 1 & 2Mining · 4.1 mi
- Silver StreakMining · 4.1 mi
- Golden Sunset MineMining · 4.1 mi
- Redemption #1 and #2 and Silver Streak MinesMining · 4.2 mi
- American Gold MineMining · 4.8 mi
- Dry Creek MineMining · 5.7 mi
- Gildersleeve MineMining · 6.9 mi
- Illinois PeakMining · 7.0 mi
- North Fork ClaimsMining · 7.3 mi
- North Fork Claims 1, 2 & 3Mining · 7.3 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Mineral 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 Mineral County.
Sources Checked
across Mineral County
Severity Distribution
across Mineral County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Mineral County, Mining runs higher than the national average — 139 sites across Mineral 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 Mineral 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 Mineral County average
Your land is one point inside Mineral County
Everything above resolves to Mineral County as a whole — one PHZM band and one county frost record, read across 781K 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 Mineral County Average
Mineral County Average
- ●USDA Zones 6a, averaged across Mineral County
- ●One soil character for all of Mineral County
- ●Frost dates read at Mineral County's scale: May 10 to Oct 7
YOUR Parcel
- ✓Your exact zone, not Mineral County's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Mineral County
Pull a site-specific report for your exact address in Mineral County, Montana — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Mineral County averages can't show:
We read public map data around Mineral County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Mineral County average
How we know this about Mineral 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 Mineral County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Mineral County
When does frost risk typically end in Mineral County?
The last hard freeze (28°F) in Mineral County typically lands around May 10, 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 31.
How long is the growing season in Mineral County?
Measured between 28°F hard freezes, Mineral County sees about 150 frost-free days — roughly May 10 through Oct 7, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 31 to Sep 23, about 115 days.
Is the soil safe to grow vegetables in Mineral County?
The federal record around Mineral County runs heavier than most — 203 documented sites, mostly Mining entries (139), the nearest Mining record about 2.3 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.
Everything above is measured at Mineral County's scale — its 6a band and its 150-day season. Your yard writes its own version of Mineral 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 Mineral County’s own scale
8 of the readings below were taken at Mineral County's own scale — its own ~150-day span between 28°F freezes, the 3 most extensive soil series mapped here and 203 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Mineral County's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Mineral County's own 28°F hard-freeze dates and its ~150-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Mineral CountyUSDA NRCS SSURGO
- 203 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Mining record about 2.3 miles outFederal environmental registers
- Mineral County's boundary and the 780,556 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~150-day seasonGrowable Ground crop-matching engine
- Mineral County sitting wholly inside the Northern RockiesUS EPA Level III Ecoregions
- Which agricultural compounds go onto Mineral 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 Mineral County — the ~150 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 Mineral County's 780,556 acreswhy one lot differs from the next →
- Which of those 203 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 Mineral Countyread your own land →