Custer, Montana, sits in USDA hardiness zone 4b — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Well-matched crops include cabbage, cranberry, turkish rocket, and collard greens, and the gap between "grows in the area" and "grows in your yard" is closed by soil, sun, and drainage.
Even in Custer, 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 Custer 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 Custer — soil, climate, flood, and parcel records. How we handle your address.
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Custer — the short answer
Custer, Montana: USDA zone 4b, about 165 days between hard freezes, across 202 acres of town.
- USDA zone
- 4b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 25
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 7
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~165
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 202 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 4b is Custer's average, not your lot's — a low corner or a tree line moves it. Against Custer's 165-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Custer
Each reading below is measured for Custer itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredCuster runs about 165 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
MeasuredCuster sits in USDA hardiness zone 4b.
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 Custer is in
Custer sits in the Northwestern Great Plains — EPA Level III, inside the wider Great Plains. That is read at Custer's own centroid rather than borrowed from Yellowstone County.
What Grows in Custer
Every plant below cleared Custer's own zone 4b and its 165-day season. Each card opens that plant's Montana profile. How we score.
Is it too late to plant in Custer?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Mar 28; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 25 (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. As the window narrows, the plantings just get faster — fall brassicas, then greens, then garlic to finish.
What's on the federal record near Custer
Closest first, within ~10 miles of Custer. Listing isn't leaking, and distance isn't exposure.
- CUSTER SERVICE CENTERUnderground Storage Tanks · 150 ft
- OLD GAS STATION CUSTERUnderground Storage Tanks · 150 ft
- BN CUSTERUnderground Storage Tanks · 200 ft
- KEMPH LAND & LIVESTOCK CO USTUnderground Storage Tanks · 200 ft
- RALPH BOTTSUnderground Storage Tanks · 200 ft
- MDOT CUSTER SITEUnderground Storage Tanks · 200 ft
- JOHN C ROAN 5601863Underground Storage Tanks · 350 ft
- TRAIL EXXON SERVICEUnderground Storage Tanks · 500 ft
- CUSTER STATIONUnderground Storage Tanks · 700 ft
- KELLER LAND & CATTLEUnderground Storage Tanks · 1600 ft
- 05N33E26D 01Nitrate · 1.6 mi
- CATTLE DEVELOPMENT CENTERCAFO · 1.8 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Custer'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 Custer.
Total Sites
44
within ~10 miles of Custer
Risk Level
Low
Highest-severity
1 concentrated animal feeding operation
Sources Checked
within ~10 miles of Custer
Severity Distribution
within ~10 miles of Custer
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Custer, Nitrate runs higher than the national average — 32 sites within ~10 miles of Custer. 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.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Custer
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 Custer average
Your land is one point inside Custer
Everything above resolves to Custer as a whole — one PHZM band and one 28°F frost record, read across 202 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 town 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 Custer Average
Custer Average
- ●USDA Zones 4b, averaged across Custer
- ●One soil character for all of Custer
- ●Frost dates read at Custer's scale: Apr 25 to Oct 7
YOUR Parcel
- ✓Your exact zone, not Custer's 4b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Custer
Pull a site-specific report for your exact address in Custer, Montana — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Custer averages can't show:
We read public map data around Custer — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Custer average
How we know this about Custer
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this town’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Custer’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 town grain anywhere on this page — there is no town-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 Custer
When does frost risk typically end in Custer?
The last hard freeze (28°F) in Custer typically lands around Apr 25, 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 16.
When is the first frost in Custer?
The first hard freeze (28°F) in Custer typically arrives around Oct 7, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 23, so the watching starts about Sep 7 — about 165 days after the spring freeze cleared.
How long is the growing season in Custer?
Measured between 28°F hard freezes, Custer sees about 165 frost-free days — roughly Apr 25 through Oct 7, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 16 to Sep 23, about 130 days.
Is the soil safe to grow vegetables in Custer?
The federal record around Custer is light — 44 documented sites across the 9 federal source types we checked, mostly Nitrate entries (32), the nearest Underground Storage Tanks record under a tenth of a mile out — and proximity to a documented site is information, not a diagnosis of any one yard. Growing food here starts from a strong position; a soil test before new food beds settles any site-specific question.
How do I protect my plants from frost in Custer?
From about Sep 7 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 7 (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 7. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Custer's scale — its 4b band and its 165-day season. Your yard writes its own version of Custer'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 Custer’s own scale
6 of the readings below were taken at Custer's own scale — its own ~165-day season between 28°F freezes, the 202 acres it covers and 44 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Custer's own USDA hardiness band, zones 4bUSDA PHZM 2023
- Custer's own 28°F hard-freeze dates, about Apr 25 and Oct 7 and the ~165-day span between themNOAA 1991–2020 Climate Normals
- 44 documented contamination sites on the federal record near Custer, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- Custer's boundary and the 202 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4b and a ~165-day seasonGrowable Ground crop-matching engine
- The ecoregion at Custer's own centroid, the Northwestern Great PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Custer's 202 acres read through its county's SSURGO summaryfrom Yellowstone County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Yellowstone 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 Yellowstone County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Custer's 202 acreswhy one lot differs from the next →
- Which side of Custer you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 202 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record under a tenth of a mile 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 Custer-wide figureread your own land →
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