Blackfoot, Montana, sits in USDA hardiness zone 4a — a zone band wide enough that plant choice, not possibility, is the interesting question.
On paper, cabbage, cranberry, cilantro, and collard greens all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Even in Blackfoot, 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 Blackfoot 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 Blackfoot — soil, climate, flood, and parcel records. How we handle your address.
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Blackfoot — the short answer
Blackfoot, Montana: USDA zone 4a, about 143 days between hard freezes, across 217 acres of town.
- USDA zone
- 4a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 7
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Sep 27
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~143
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 217 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 4a is Blackfoot's average, not your lot's — a low corner or a tree line moves it. Against Blackfoot's 143-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Blackfoot
Each reading below is measured for Blackfoot itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredBlackfoot runs about 143 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
MeasuredBlackfoot sits in USDA hardiness zone 4a.
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 Blackfoot is in
Blackfoot sits in the Northwestern Glaciated Plains — EPA Level III, inside the wider Great Plains. That is read at Blackfoot's own centroid rather than borrowed from Glacier County.
What Grows in Blackfoot
Every plant below cleared Blackfoot's own zone 4a and its 143-day season. Each card opens that plant's Montana profile. How we score.
Is it too late to plant in Blackfoot?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Apr 9; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 7 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Sep 27 — long-season crops need about 90 days of runway, quick greens only 30. Short seasons reward decisiveness — quick-maturing varieties late, hardy greens under cover, and next year’s garlic in the ground before it closes.
What's on the federal record near Blackfoot
Closest first, within ~10 miles of Blackfoot. Listing isn't leaking, and distance isn't exposure.
- 33N10W35AADC01Nitrate · 1400 ft
- HOYT'S TOWINGBrownfields · 1.0 mi
- BOND'S BODY SHOPBrownfields · 1.0 mi
- BIA-BLACKFEET INDIAN RESERVATIONSuperfund · 2.4 mi
- 32N10W15BDBA01Nitrate · 2.9 mi
- 32N09W19DACA01Nitrate · 4.8 mi
- 33N09W22BBBB01Nitrate · 4.9 mi
- 32N10W18CDDB01Nitrate · 5.1 mi
- 33N10W08BAAB01Nitrate · 5.3 mi
- 32N10W19DBDB01Nitrate · 5.5 mi
- 32N10W19DDBA01Nitrate · 5.5 mi
- 32N10W19DBBC01Nitrate · 5.5 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Blackfoot'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 Blackfoot.
Total Sites
85
within ~10 miles of Blackfoot
Risk Level
Elevated
Highest-severity
3 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Blackfoot
Severity Distribution
within ~10 miles of Blackfoot
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Blackfoot, two things run higher than the national average within ~10 miles of Blackfoot — Superfund (3 sites) and Nitrate (44 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Blackfoot
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 Blackfoot average
Your land is one point inside Blackfoot
Everything above resolves to Blackfoot as a whole — one PHZM band and one 28°F frost record, read across 217 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 Blackfoot Average
Blackfoot Average
- ●USDA Zones 4a, averaged across Blackfoot
- ●One soil character for all of Blackfoot
- ●Frost dates read at Blackfoot's scale: May 7 to Sep 27
YOUR Parcel
- ✓Your exact zone, not Blackfoot's 4a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Blackfoot
Pull a site-specific report for your exact address in Blackfoot, Montana — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Blackfoot averages can't show:
We read public map data around Blackfoot — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Blackfoot average
How we know this about Blackfoot
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 Blackfoot’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 Blackfoot
When does frost risk typically end in Blackfoot?
The last hard freeze (28°F) in Blackfoot typically lands around May 7, 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 28.
When is the first frost in Blackfoot?
The first hard freeze (28°F) in Blackfoot typically arrives around Sep 27, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 13, so the watching starts about Aug 28 — about 143 days after the spring freeze cleared.
How long is the growing season in Blackfoot?
Measured between 28°F hard freezes, Blackfoot sees about 143 frost-free days — roughly May 7 through Sep 27, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 28 to Sep 13, about 108 days.
Is the soil safe to grow vegetables in Blackfoot?
The federal record around Blackfoot is a meaningful one — 85 documented sites, mostly Nitrate entries (44), the nearest Nitrate 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 Blackfoot?
With about 143 frost-free days between hard freezes, Blackfoot 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 171 to 199 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 7 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Blackfoot's scale — its 4a band and its 143-day season. Your yard writes its own version of Blackfoot'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 Blackfoot’s own scale
6 of the readings below were taken at Blackfoot's own scale — its own ~143-day season between 28°F freezes, the 217 acres it covers and 85 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Blackfoot's own USDA hardiness band, zones 4aUSDA PHZM 2023
- Blackfoot's own 28°F hard-freeze dates, about May 7 and Sep 27 and the ~143-day span between themNOAA 1991–2020 Climate Normals
- 85 documented contamination sites on the federal record near Blackfoot, the closest Nitrate record about 0.3 miles out from the town centreFederal environmental registers
- Blackfoot's boundary and the 217 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4a and a ~143-day seasonGrowable Ground crop-matching engine
- The ecoregion at Blackfoot's own centroid, the Northwestern Glaciated PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Blackfoot's 217 acres read through its county's SSURGO summaryfrom Glacier County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Glacier 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 Glacier County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Blackfoot's 217 acreswhy one lot differs from the next →
- Which side of Blackfoot you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 217 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate 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 Blackfoot-wide figureread your own land →