Duncan Ranch Colony, Montana, sits in USDA hardiness zone 4b — a zone band wide enough that plant choice, not possibility, is the interesting question.
These conditions suit cabbage, cranberry, cilantro, and collard greens — a starting list any specific site will trim or extend with its own soil, sun, and drainage.
Even in Duncan Ranch Colony, 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 Duncan Ranch Colony 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 Duncan Ranch Colony — soil, climate, flood, and parcel records. How we handle your address.
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Duncan Ranch Colony — the short answer
Duncan Ranch Colony, Montana: USDA zone 4b, about 141 days between hard freezes, across 387 acres of town.
- USDA zone
- 4b
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 10
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Sep 28
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~141
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 387 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 Duncan Ranch Colony's average, not your lot's — a low corner or a tree line moves it. Against Duncan Ranch Colony's 141-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Duncan Ranch Colony
Each reading below is measured for Duncan Ranch Colony itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredDuncan Ranch Colony runs about 141 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
MeasuredDuncan Ranch Colony 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 Duncan Ranch Colony is in
Duncan Ranch Colony sits in the Northwestern Great Plains — EPA Level III, inside the wider Great Plains. That is read at Duncan Ranch Colony's own centroid rather than borrowed from Wheatland County.
What Grows in Duncan Ranch Colony
Every plant below cleared Duncan Ranch Colony's own zone 4b and its 141-day season. Each card opens that plant's Montana profile. How we score.
Is it too late to plant in Duncan Ranch Colony?
Almost never — the real question is what to plant next. 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 Sep 28 — 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.
What's on the federal record near Duncan Ranch Colony
Closest first, within ~10 miles of Duncan Ranch Colony. Listing isn't leaking, and distance isn't exposure.
- DUNCAN RANCH COLONYCAFO · 1400 ft
- MILWAUKEE RAILROAD MONTANA SUBSTATIONSSuperfund · 2.3 mi
- HeathMining · 4.2 mi
- TWODOT MICROWAVE SITEUnderground Storage Tanks · 7.8 mi
- AMERICAN FORK RANCH TWODOTUnderground Storage Tanks · 7.8 mi
- AMERICAN FORK RANCH BIG ELKUnderground Storage Tanks · 7.8 mi
- LAMMERS FEED & SEED INCUnderground Storage Tanks · 8.8 mi
- TOWN PUMP INC HARLOWTONUnderground Storage Tanks · 8.8 mi
- HARLOWTON SHOPUnderground Storage Tanks · 9.0 mi
- WHEATLAND IMPLEMENT & REPAIRUnderground Storage Tanks · 9.1 mi
- MALMSTROM AFB K 6Underground Storage Tanks · 9.1 mi
- MALMSTROM AFB K 9Underground Storage Tanks · 9.1 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Duncan Ranch Colony'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 Duncan Ranch Colony.
Total Sites
42
within ~10 miles of Duncan Ranch Colony
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Duncan Ranch Colony
Severity Distribution
within ~10 miles of Duncan Ranch Colony
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Duncan Ranch Colony, Underground Storage Tanks runs higher than the national average — 38 sites within ~10 miles of Duncan Ranch Colony. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Duncan Ranch Colony
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 Duncan Ranch Colony average
Your land is one point inside Duncan Ranch Colony
Everything above resolves to Duncan Ranch Colony as a whole — one PHZM band and one 28°F frost record, read across 387 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 Duncan Ranch Colony Average
Duncan Ranch Colony Average
- ●USDA Zones 4b, averaged across Duncan Ranch Colony
- ●One soil character for all of Duncan Ranch Colony
- ●Frost dates read at Duncan Ranch Colony's scale: May 10 to Sep 28
YOUR Parcel
- ✓Your exact zone, not Duncan Ranch Colony's 4b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Duncan Ranch Colony
Pull a site-specific report for your exact address in Duncan Ranch Colony, Montana — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Duncan Ranch Colony averages can't show:
We read public map data around Duncan Ranch Colony — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Duncan Ranch Colony average
How we know this about Duncan Ranch Colony
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 Duncan Ranch Colony’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 Duncan Ranch Colony
When does frost risk typically end in Duncan Ranch Colony?
The last hard freeze (28°F) in Duncan Ranch Colony 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.
When is the first frost in Duncan Ranch Colony?
The first hard freeze (28°F) in Duncan Ranch Colony typically arrives around Sep 28, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 14, so the watching starts about Aug 29 — about 141 days after the spring freeze cleared.
How long is the growing season in Duncan Ranch Colony?
Measured between 28°F hard freezes, Duncan Ranch Colony sees about 141 frost-free days — roughly May 10 through Sep 28, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 31 to Sep 14, about 106 days.
Is the soil safe to grow vegetables in Duncan Ranch Colony?
The federal record around Duncan Ranch Colony is a meaningful one — 42 documented sites, mostly Underground Storage Tanks entries (38), the nearest CAFO record about 0.3 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 Duncan Ranch Colony?
With about 141 frost-free days between hard freezes, Duncan Ranch Colony 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 169 to 197 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 10 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Duncan Ranch Colony's scale — its 4b band and its 141-day season. Your yard writes its own version of Duncan Ranch Colony'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 Duncan Ranch Colony’s own scale
6 of the readings below were taken at Duncan Ranch Colony's own scale — its own ~141-day season between 28°F freezes, the 387 acres it covers and 42 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Duncan Ranch Colony's own USDA hardiness band, zones 4bUSDA PHZM 2023
- Duncan Ranch Colony's own 28°F hard-freeze dates, about May 10 and Sep 28 and the ~141-day span between themNOAA 1991–2020 Climate Normals
- 42 documented contamination sites on the federal record near Duncan Ranch Colony, the closest CAFO record about 0.3 miles out from the town centreFederal environmental registers
- Duncan Ranch Colony's boundary and the 387 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4b and a ~141-day seasonGrowable Ground crop-matching engine
- The ecoregion at Duncan Ranch Colony's own centroid, the Northwestern Great PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Duncan Ranch Colony's 387 acres read through its county's SSURGO summaryfrom Wheatland County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Wheatland 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 Wheatland County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Duncan Ranch Colony's 387 acreswhy one lot differs from the next →
- Which side of Duncan Ranch Colony you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 387 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest CAFO record about 0.3 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 Duncan Ranch Colony-wide figureread your own land →
More in Montana
Wider growing context
What grows across MontanaDuncan Ranch Colony sits outside our named growing regions, so Montana as a whole is its closest context here.
Nearby growing guides