Libby, 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.
Even in Libby, no two yards are alike.
A low spot, a south-facing slope, or a stand of trees moves the frost date and sun across a single Libby lot. 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 Libby — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Libby — the short answer
Libby, Montana: USDA zone 6a, about 158 days between hard freezes, across 1K acres of city.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 1
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 6
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~158
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 1K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are this town’s own 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 Libby's average, not your lot's — a low corner or a tree line moves it. Against Libby's 158-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Libby
Each reading below is measured for Libby itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredLibby runs about 158 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
MeasuredLibby 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 Libby is in
Libby sits in the Northern Rockies — EPA Level III, inside the wider Northwestern Forested Mountains. That is read at Libby's own centroid rather than borrowed from Lincoln County.
What Grows in Libby
Every plant below cleared Libby's own zone 6a and its 158-day season. Each card opens that plant's Montana profile. How we score.
Is it too late to plant in Libby?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. Cool-season crops can go in from around Apr 3; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 1 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 6 — long-season crops need about 90 days of runway, quick greens only 30. As the window narrows, the plantings just get faster — fall brassicas, then greens, then garlic to finish.
What's on the federal record near Libby
Closest first, within ~10 miles of Libby. Listing isn't leaking, and distance isn't exposure.
- AITKENS QUIK STOP INCUnderground Storage Tanks · 700 ft
- SUNRISE RENTALUnderground Storage Tanks · 700 ft
- BIG SKY CONOCO LIBBYUnderground Storage Tanks · 800 ft
- POP SHOPPE MEL PARKERUnderground Storage Tanks · 1000 ft
- TOWN PUMP INC LIBBYUnderground Storage Tanks · 1000 ft
- LIBBY PUBLIC SCHOOLS MAINTENANCE SHOPBrownfields · 1000 ft
- LIBBY DAMUnderground Storage Tanks · 1100 ft
- BN KING MOUNTAIN COMPUTER 28Underground Storage Tanks · 1100 ft
- BN LIBBY PRINT 324 COMPUTER 23 & 24Underground Storage Tanks · 1100 ft
- LIBBY SUBSTATIONUnderground Storage Tanks · 1100 ft
- LOUISIANA PACIFIC CORP LIBBYUnderground Storage Tanks · 1100 ft
- LINCOLN COUNTY ROAD DEPTUnderground Storage Tanks · 1100 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Libby'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 Libby.
Sources Checked
within ~10 miles of Libby
Severity Distribution
within ~10 miles of Libby
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Libby, two things run higher than the national average within ~10 miles of Libby — Nitrate (150 sites) and Mining (25 sites). That's not a problem with your land — it's information about it.
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 Libby
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 Libby average
Your land is one point inside Libby
Everything above resolves to Libby as a whole — one PHZM band and one 28°F frost record, read across 1K 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 city 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 local average.
Your Lot vs the Libby Average
Libby Average
- ●USDA Zones 6a, averaged across Libby
- ●One soil character for all of Libby
- ●Frost dates read at Libby's scale: May 1 to Oct 6
YOUR Parcel
- ✓Your exact zone, not Libby's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Libby
Pull a site-specific report for your exact address in Libby, Montana — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Libby averages can't show:
We read public map data around Libby — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Libby average
How we know this about Libby
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this city’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Libby’s own record; boundaries and acreage from US Census TIGER/Line 2025; the contamination records from the federal sources named in their beats above. Soil is not read at city grain anywhere on this page — there is no city-resolution survey in our data, which is why you will find no soil grid here rather than a statewide one wearing a local label. The resolution ledger below names every figure this page inherited.
Common questions about Libby
When does frost risk typically end in Libby?
The last hard freeze (28°F) in Libby typically lands around May 1, 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 22.
When is the first frost in Libby?
The first hard freeze (28°F) in Libby typically arrives around Oct 6, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 22, so the watching starts about Sep 6 — about 158 days after the spring freeze cleared.
How long is the growing season in Libby?
Measured between 28°F hard freezes, Libby sees about 158 frost-free days — roughly May 1 through Oct 6, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 22 to Sep 22, about 123 days.
Is the soil safe to grow vegetables in Libby?
The federal record around Libby runs heavier than most — 256 documented sites, mostly Nitrate entries (150), the nearest Underground Storage Tanks record about 0.1 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 I protect my plants from frost in Libby?
From about Sep 6 the job here turns from planting to protecting — the last start even a 30-day crop can finish. As the season closes around the first 28°F hard freeze near Oct 6 (NOAA 1991–2020 climate normals), three moves buy time: row cover or an old sheet over tender plants on still, clear nights; water the soil the afternoon before a freeze, so it holds warmth overnight; and harvest tomatoes, peppers and basil before Oct 6. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Libby's scale — its 6a band and its 158-day season. Your yard writes its own version of Libby's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
What this page reads at Libby’s own scale
6 of the readings below were taken at Libby's own scale — its own ~158-day season between 28°F freezes, the 1,179 acres it covers and 256 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Libby's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Libby's own 28°F hard-freeze dates, about May 1 and Oct 6 and the ~158-day span between themNOAA 1991–2020 Climate Normals
- 256 documented contamination sites on the federal record near Libby, the closest Underground Storage Tanks record about 0.1 miles out from the town centreFederal environmental registers
- Libby's boundary and the 1,179 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~158-day seasonGrowable Ground crop-matching engine
- The ecoregion at Libby's own centroid, the Northern RockiesUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Libby's 1,179 acres read through its county's SSURGO summaryfrom Lincoln County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Lincoln County
- The growing challenges every Montana grower plans around — written at state scale, so they stay on the state guidefrom Montana
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Lincoln County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Libby's 1,179 acreswhy one lot differs from the next →
- Which side of Libby you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,179 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.1 miles out, measured from the town centrehow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — measured at your address, and averaged away by any Libby-wide figureread your own land →
More in Montana
Wider growing context
What grows across MontanaLibby sits outside our named growing regions, so Montana as a whole is its closest context here.
Nearby growing guides