East Helena, Montana, sits in USDA hardiness zone 4b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
A short list that earns its place here — cabbage, cranberry, turkish rocket, and collard greens — with any one site's soil, sun, and drainage making the final cut.
Even in East Helena, 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 East Helena 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 East Helena — soil, climate, flood, and parcel records. How we handle your address.
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East Helena — the short answer
East Helena, Montana: USDA zone 4b, about 161 days between hard freezes, across 3K acres of city.
- USDA zone
- 4b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 30
- 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
- ~161
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 3K 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 East Helena's average, not your lot's — a low corner or a tree line moves it. Against East Helena's 161-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in East Helena
Each reading below is measured for East Helena itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredEast Helena runs about 161 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
MeasuredEast Helena 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 East Helena is in
East Helena sits in the Middle Rockies — EPA Level III, inside the wider Northwestern Forested Mountains. That is read at East Helena's own centroid rather than borrowed from Lewis and Clark County.
What Grows in East Helena
Every plant below cleared East Helena's own zone 4b and its 161-day season. Each card opens that plant's Montana profile. How we score.
Is it too late to plant in East Helena?
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 2; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 30 (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. As the window narrows, the plantings just get faster — fall brassicas, then greens, then garlic to finish.
What's on the federal record near East Helena
Closest first, within ~10 miles of East Helena. Listing isn't leaking, and distance isn't exposure.
- EAST HELENA SITESuperfund · 250 ft
- AMERICAN CHEMETToxics Release Inventory · 1000 ft
- ASARCO SODIUM - EAST HELENASuperfund · 1500 ft
- EXXON MOBIL CORP HELENA TERMINALToxics Release Inventory · 1600 ft
- AMERICAN CHEMET CORPBrownfields · 1700 ft
- East Helena Plant AsarcoMining · 1800 ft
- CITY OF EAST HELENA USTUnderground Storage Tanks · 1800 ft
- DOROTHY VIETHUnderground Storage Tanks · 1800 ft
- NOONS 415Underground Storage Tanks · 1900 ft
- FORMER EAST HELENA COLOR TV REPAIRUnderground Storage Tanks · 1900 ft
- ASARCOToxics Release Inventory · 1900 ft
- ASARCOBrownfields · 1900 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from East Helena'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 East Helena.
Sources Checked
within ~10 miles of East Helena
Severity Distribution
within ~10 miles of East Helena
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around East Helena, two things run higher than the national average within ~10 miles of East Helena — Nitrate (634 sites) and Mining (107 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around 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 East Helena
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 East Helena average
Your land is one point inside East Helena
Everything above resolves to East Helena as a whole — one PHZM band and one 28°F frost record, read across 3K 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 East Helena Average
East Helena Average
- ●USDA Zones 4b, averaged across East Helena
- ●One soil character for all of East Helena
- ●Frost dates read at East Helena's scale: Apr 30 to Oct 8
YOUR Parcel
- ✓Your exact zone, not East Helena's 4b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in East Helena
Pull a site-specific report for your exact address in East Helena, Montana — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that East Helena averages can't show:
We read public map data around East Helena — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the East Helena average
How we know this about East Helena
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 East Helena’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 East Helena
When does frost risk typically end in East Helena?
The last hard freeze (28°F) in East Helena typically lands around Apr 30, 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 21.
When is the first frost in East Helena?
The first hard freeze (28°F) in East Helena 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 161 days after the spring freeze cleared.
How long is the growing season in East Helena?
Measured between 28°F hard freezes, East Helena sees about 161 frost-free days — roughly Apr 30 through Oct 8, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 21 to Sep 24, about 126 days.
Is the soil safe to grow vegetables in East Helena?
The federal record around East Helena runs heavier than most — 1,096 documented sites, mostly Nitrate entries (634), the nearest Superfund 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 East Helena?
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 East Helena's scale — its 4b band and its 161-day season. Your yard writes its own version of East Helena'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 East Helena’s own scale
6 of the readings below were taken at East Helena's own scale — its own ~161-day season between 28°F freezes, the 2,595 acres it covers and 1,096 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- East Helena's own USDA hardiness band, zones 4bUSDA PHZM 2023
- East Helena's own 28°F hard-freeze dates, about Apr 30 and Oct 8 and the ~161-day span between themNOAA 1991–2020 Climate Normals
- 1,096 documented contamination sites on the federal record near East Helena, the closest Superfund record under a tenth of a mile out from the town centreFederal environmental registers
- East Helena's boundary and the 2,595 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4b and a ~161-day seasonGrowable Ground crop-matching engine
- The ecoregion at East Helena's own centroid, the Middle RockiesUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so East Helena's 2,595 acres read through its county's SSURGO summaryfrom Lewis and Clark County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Lewis and Clark 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 Lewis and Clark County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among East Helena's 2,595 acreswhy one lot differs from the next →
- Which side of East Helena you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 2,595 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Superfund 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 East Helena-wide figureread your own land →
More in Montana
Wider growing context
What grows across MontanaEast Helena sits outside our named growing regions, so Montana as a whole is its closest context here.
Nearby growing guides