Radersburg, Montana, sits in USDA hardiness zone 5a — a zone band wide enough that plant choice, not possibility, is the interesting question.
Among the crops suited to this profile: cabbage, cranberry, lavender, and collard greens. The site-level story — soil, sun, drainage — decides the rest.
Even in Radersburg, 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 Radersburg 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 Radersburg — soil, climate, flood, and parcel records. How we handle your address.
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Radersburg — the short answer
Radersburg, Montana: USDA zone 5a, about 160 days between hard freezes, across 161 acres of town.
- USDA zone
- 5a
- 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 8
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~160
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 161 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 5a is Radersburg's average, not your lot's — a low corner or a tree line moves it. Against Radersburg's 160-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Radersburg
Each reading below is measured for Radersburg itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredRadersburg runs about 160 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
MeasuredRadersburg sits in USDA hardiness zone 5a.
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 Radersburg is in
Radersburg sits in the Middle Rockies — EPA Level III, inside the wider Northwestern Forested Mountains. That is read at Radersburg's own centroid rather than borrowed from Broadwater County.
What Grows in Radersburg
Every plant below cleared Radersburg's own zone 5a and its 160-day season. Each card opens that plant's Montana profile. How we score.
Is it too late to plant in Radersburg?
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 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 8 — long-season crops need about 90 days of runway, quick greens only 30. The tail of the season still works: sixty-day crops into late summer, quick greens after, garlic last of all.
What's on the federal record near Radersburg
Closest first, within ~10 miles of Radersburg. Listing isn't leaking, and distance isn't exposure.
- M & M GROCERYUnderground Storage Tanks · 400 ft
- BUTCH MCGEE RESIDENCEBrownfields · 800 ft
- IRON CROSS MINEUnderground Storage Tanks · 1400 ft
- TOSTON SHOPUnderground Storage Tanks · 1400 ft
- AT & T RADIO TOWER TOSTONUnderground Storage Tanks · 1400 ft
- RenaMining · 1.3 mi
- GENEVA MILLUnderground Storage Tanks · 1.5 mi
- Keating GroupMining · 1.6 mi
- RadersburgMining · 1.7 mi
- Ohio - Keating MineMining · 1.9 mi
- 05N01E22BBAB01Nitrate · 2.1 mi
- Donald DeeMining · 2.3 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Radersburg'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 Radersburg.
Total Sites
193
within ~10 miles of Radersburg
Risk Level
High
Highest-severity
2 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Radersburg
Severity Distribution
within ~10 miles of Radersburg
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Radersburg, two things run higher than the national average within ~10 miles of Radersburg — Mining (81 sites) and Nitrate (82 sites). That's not a problem with your land — it's information about it.
Mining: Mining sites — both historic and active — can leach heavy metals (arsenic, lead, cadmium, mercury) into soil and water for centuries after operations cease.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Radersburg
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 Radersburg average
Your land is one point inside Radersburg
Everything above resolves to Radersburg as a whole — one PHZM band and one 28°F frost record, read across 161 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 Radersburg Average
Radersburg Average
- ●USDA Zones 5a, averaged across Radersburg
- ●One soil character for all of Radersburg
- ●Frost dates read at Radersburg's scale: May 1 to Oct 8
YOUR Parcel
- ✓Your exact zone, not Radersburg's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Radersburg
Pull a site-specific report for your exact address in Radersburg, Montana — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Radersburg averages can't show:
We read public map data around Radersburg — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Radersburg average
How we know this about Radersburg
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 Radersburg’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 Radersburg
When does frost risk typically end in Radersburg?
The last hard freeze (28°F) in Radersburg 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 Radersburg?
The first hard freeze (28°F) in Radersburg typically arrives around Oct 8, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 24, so the watching starts about Sep 8 — about 160 days after the spring freeze cleared.
How long is the growing season in Radersburg?
Measured between 28°F hard freezes, Radersburg sees about 160 frost-free days — roughly May 1 through Oct 8, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 22 to Sep 24, about 125 days.
Is the soil safe to grow vegetables in Radersburg?
The federal record around Radersburg runs heavier than most — 193 documented sites, mostly Nitrate entries (82), the nearest Underground Storage Tanks record under a tenth of a mile 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 Radersburg?
From about Sep 8 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 8 (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 8. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Radersburg's scale — its 5a band and its 160-day season. Your yard writes its own version of Radersburg'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 Radersburg’s own scale
6 of the readings below were taken at Radersburg's own scale — its own ~160-day season between 28°F freezes, the 161 acres it covers and 193 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Radersburg's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Radersburg's own 28°F hard-freeze dates, about May 1 and Oct 8 and the ~160-day span between themNOAA 1991–2020 Climate Normals
- 193 documented contamination sites on the federal record near Radersburg, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- Radersburg's boundary and the 161 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~160-day seasonGrowable Ground crop-matching engine
- The ecoregion at Radersburg's own centroid, the Middle RockiesUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Radersburg's 161 acres read through its county's SSURGO summaryfrom Broadwater County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Broadwater 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 Broadwater County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Radersburg's 161 acreswhy one lot differs from the next →
- Which side of Radersburg you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 161 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 Radersburg-wide figureread your own land →
More in Montana
Wider growing context
What grows across MontanaRadersburg sits outside our named growing regions, so Montana as a whole is its closest context here.