Alder, Montana, sits in USDA hardiness zone 5a — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
Expect cabbage, cranberry, lavender, and collard greens to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
Even in Alder, 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 Alder 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 Alder — soil, climate, flood, and parcel records. How we handle your address.
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Alder — the short answer
Alder, Montana: USDA zone 5a, about 139 days between hard freezes, across 1K acres of town.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 13
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Sep 29
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~139
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 1K 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 Alder's average, not your lot's — a low corner or a tree line moves it. Against Alder's 139-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Alder
Each reading below is measured for Alder itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredAlder runs about 139 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
MeasuredAlder 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 Alder is in
Alder sits in the Middle Rockies — EPA Level III, inside the wider Northwestern Forested Mountains. That is read at Alder's own centroid rather than borrowed from Madison County.
What Grows in Alder
Every plant below cleared Alder's own zone 5a and its 139-day season. Each card opens that plant's Montana profile. How we score.
Is it too late to plant in Alder?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. Cool-season crops can go in from around Apr 15; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 13 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Sep 29 — long-season crops need about 90 days of runway, quick greens only 30. Even here the calendar’s edges hold value: thirty-day greens late in the window, then garlic and a rested bed for spring.
What's on the federal record near Alder
Closest first, within ~10 miles of Alder. Listing isn't leaking, and distance isn't exposure.
- MADISON COUNTY ROAD DEPT SHOPUnderground Storage Tanks · 950 ft
- ALDER WASH PLANTUnderground Storage Tanks · 950 ft
- SMAIL CONST INCUnderground Storage Tanks · 1000 ft
- ALDER KOAUnderground Storage Tanks · 1000 ft
- SNOWCREST RANCHUnderground Storage Tanks · 1000 ft
- ALDER MARKET LLCUnderground Storage Tanks · 1100 ft
- BERNARD HANSONUnderground Storage Tanks · 1800 ft
- 06S04W10CDCC01Nitrate · 1.3 mi
- RUBY VALLEY PRESSURE TREATINGBrownfields · 1.4 mi
- 06S04W06DBAB01Nitrate · 1.9 mi
- 06S04W28BDAA01Nitrate · 2.4 mi
- Black MagicMining · 4.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Alder'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 Alder.
Sources Checked
within ~10 miles of Alder
Severity Distribution
within ~10 miles of Alder
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Alder, Mining runs higher than the national average — 51 sites within ~10 miles of Alder. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
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 soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Check your specific parcel in Alder
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 Alder average
Your land is one point inside Alder
Everything above resolves to Alder as a whole — one PHZM band and one 28°F frost record, read across 1K 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 Alder Average
Alder Average
- ●USDA Zones 5a, averaged across Alder
- ●One soil character for all of Alder
- ●Frost dates read at Alder's scale: May 13 to Sep 29
YOUR Parcel
- ✓Your exact zone, not Alder's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Alder
Pull a site-specific report for your exact address in Alder, Montana — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Alder averages can't show:
We read public map data around Alder — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Alder average
How we know this about Alder
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 Alder’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 Alder
When does frost risk typically end in Alder?
The last hard freeze (28°F) in Alder typically lands around May 13, 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 Jun 3.
When is the first frost in Alder?
The first hard freeze (28°F) in Alder typically arrives around Sep 29, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 15, so the watching starts about Aug 30 — about 139 days after the spring freeze cleared.
How long is the growing season in Alder?
Measured between 28°F hard freezes, Alder sees about 139 frost-free days — roughly May 13 through Sep 29, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 3 to Sep 15, about 104 days.
Is the soil safe to grow vegetables in Alder?
The federal record around Alder runs heavier than most — 82 documented sites, mostly Mining entries (51), the nearest Underground Storage Tanks record about 0.2 miles 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 gardeners stretch the season in Alder?
With about 139 frost-free days between hard freezes, Alder 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 167 to 195 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 13 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Alder's scale — its 5a band and its 139-day season. Your yard writes its own version of Alder'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 Alder’s own scale
6 of the readings below were taken at Alder's own scale — its own ~139-day season between 28°F freezes, the 1,284 acres it covers and 82 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Alder's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Alder's own 28°F hard-freeze dates, about May 13 and Sep 29 and the ~139-day span between themNOAA 1991–2020 Climate Normals
- 82 documented contamination sites on the federal record near Alder, the closest Underground Storage Tanks record about 0.2 miles out from the town centreFederal environmental registers
- Alder's boundary and the 1,284 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~139-day seasonGrowable Ground crop-matching engine
- The ecoregion at Alder's own centroid, the Middle RockiesUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Alder's 1,284 acres read through its county's SSURGO summaryfrom Madison County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Madison 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 Madison County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Alder's 1,284 acreswhy one lot differs from the next →
- Which side of Alder you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,284 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.2 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 Alder-wide figureread your own land →
More in Montana
Wider growing context
What grows across MontanaAlder sits outside our named growing regions, so Montana as a whole is its closest context here.
Nearby growing guides