Acton, Montana, sits in USDA hardiness zone 5a — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
Growers here do well with cabbage, cranberry, lavender, and collard greens — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Even in Acton, 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 Acton 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 Acton — soil, climate, flood, and parcel records. How we handle your address.
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Acton — the short answer
Acton, Montana: USDA zone 5a, about 170 days between hard freezes, across 154 acres of town.
- USDA zone
- 5a
- 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 12
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~170
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 154 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 Acton's average, not your lot's — a low corner or a tree line moves it. Against Acton's 170-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Acton
Each reading below is measured for Acton itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredActon runs about 170 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
MeasuredActon 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 Acton is in
Acton sits in the Northwestern Great Plains — EPA Level III, inside the wider Great Plains. That is read at Acton's own centroid rather than borrowed from Yellowstone County.
What Grows in Acton
Every plant below cleared Acton's own zone 5a and its 170-day season. Each card opens that plant's Montana profile. How we score.
Is it too late to plant in Acton?
For most of the year, no — what changes is which crops still fit the days remaining. 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 12 — 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 Acton
Closest first, within ~10 miles of Acton. Listing isn't leaking, and distance isn't exposure.
- 02N24E13A 01Nitrate · 1500 ft
- 02N24E12A 01Nitrate · 0.7 mi
- 02N25E19B 01Nitrate · 1.4 mi
- WILLIAM V HICKSONUnderground Storage Tanks · 1.5 mi
- 02N25E20D 01Nitrate · 2.7 mi
- 02N24E22B 01Nitrate · 2.8 mi
- 02N25E20CCDA01Nitrate · 3.2 mi
- PULZ PRODUCTBrownfields · 3.8 mi
- 02N25E22C 01Nitrate · 3.9 mi
- 03N24E26B 01Nitrate · 4.1 mi
- 02N25E34C 01Nitrate · 5.1 mi
- 01N25E04C 01Nitrate · 5.4 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Acton'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 Acton.
Total Sites
57
within ~10 miles of Acton
Risk Level
Elevated
Highest-severity
1 concentrated animal feeding operation
Sources Checked
within ~10 miles of Acton
Severity Distribution
within ~10 miles of Acton
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Acton, two things run higher than the national average within ~10 miles of Acton — PFAS (3 sites) and Nitrate (42 sites). That's not a problem with your land — it's information about it.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Acton
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 Acton average
Your land is one point inside Acton
Everything above resolves to Acton as a whole — one PHZM band and one 28°F frost record, read across 154 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 Acton Average
Acton Average
- ●USDA Zones 5a, averaged across Acton
- ●One soil character for all of Acton
- ●Frost dates read at Acton's scale: Apr 25 to Oct 12
YOUR Parcel
- ✓Your exact zone, not Acton's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Acton
Pull a site-specific report for your exact address in Acton, Montana — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Acton averages can't show:
We read public map data around Acton — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Acton average
How we know this about Acton
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 Acton’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 Acton
When does frost risk typically end in Acton?
The last hard freeze (28°F) in Acton 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 Acton?
The first hard freeze (28°F) in Acton typically arrives around Oct 12, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 28, so the watching starts about Sep 12 — about 170 days after the spring freeze cleared.
How long is the growing season in Acton?
Measured between 28°F hard freezes, Acton sees about 170 frost-free days — roughly Apr 25 through Oct 12, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 16 to Sep 28, about 135 days.
Is the soil safe to grow vegetables in Acton?
The federal record around Acton is a meaningful one — 57 documented sites, mostly Nitrate entries (42), 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 I protect my plants from frost in Acton?
From about Sep 12 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 12 (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 12. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Acton's scale — its 5a band and its 170-day season. Your yard writes its own version of Acton'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 Acton’s own scale
6 of the readings below were taken at Acton's own scale — its own ~170-day season between 28°F freezes, the 154 acres it covers and 57 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Acton's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Acton's own 28°F hard-freeze dates, about Apr 25 and Oct 12 and the ~170-day span between themNOAA 1991–2020 Climate Normals
- 57 documented contamination sites on the federal record near Acton, the closest Nitrate record about 0.3 miles out from the town centreFederal environmental registers
- Acton's boundary and the 154 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~170-day seasonGrowable Ground crop-matching engine
- The ecoregion at Acton's own centroid, the Northwestern Great PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Acton's 154 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 Acton's 154 acreswhy one lot differs from the next →
- Which side of Acton you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 154 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 Acton-wide figureread your own land →
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