Iron Mountain, Michigan, sits in USDA hardiness zone 4b — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
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 Iron Mountain, 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 Iron Mountain 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 Iron Mountain — soil, climate, flood, and parcel records. How we handle your address.
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Iron Mountain — the short answer
Iron Mountain, Michigan: USDA zone 4b, about 148 days between hard freezes, across 5K acres of city.
- USDA zone
- 4b
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 12
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 7
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~148
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 5K 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 Iron Mountain's average, not your lot's — a low corner or a tree line moves it. Against Iron Mountain's 148-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Iron Mountain
Each reading below is measured for Iron Mountain itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredIron Mountain runs about 148 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
MeasuredIron Mountain 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 Iron Mountain is in
Iron Mountain sits in the Northern Lakes and Forests — EPA Level III, inside the wider Northern Forests. That is read at Iron Mountain's own centroid rather than borrowed from Dickinson County.
What Grows in Iron Mountain
Every plant below cleared Iron Mountain's own zone 4b and its 148-day season. Each card opens that plant's Michigan profile. How we score.
Is it too late to plant in Iron Mountain?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Apr 14; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 12 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 7 — long-season crops need about 90 days of runway, quick greens only 30. When the window is tight, the fall moves are quick ones — baby greens, radishes, and garlic set for next season.
What's on the federal record near Iron Mountain
Closest first, within ~10 miles of Iron Mountain. Listing isn't leaking, and distance isn't exposure.
- North Side Self Serve MartUnderground Storage Tanks · 700 ft
- KRIST OIL COBrownfields · 750 ft
- SCHULTZ EQUIPMENT PARTS CO INCBrownfields · 750 ft
- MI DEPT/TRANSPORTATIONBrownfields · 750 ft
- ADVANCE AUTO PARTSBrownfields · 750 ft
- Krist Food Mart # 21Underground Storage Tanks · 800 ft
- Northside ServiceUnderground Storage Tanks · 800 ft
- ZAMBON DECORATING COBrownfields · 800 ft
- Midas MufflerUnderground Storage Tanks · 900 ft
- Freedom Value Center IncUnderground Storage Tanks · 900 ft
- MIDAS AUTO SYSTEMSBrownfields · 900 ft
- UNION PACIFIC RR/FORMER ANTOINE RAILYARDBrownfields · 900 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Iron Mountain'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 Iron Mountain.
Total Sites
392
within ~10 miles of Iron Mountain
Risk Level
Elevated
Highest-severity
6 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Iron Mountain
Severity Distribution
within ~10 miles of Iron Mountain
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Iron Mountain, Superfund runs higher than the national average — 6 sites within ~10 miles of Iron Mountain. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check your specific parcel in Iron Mountain
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 Iron Mountain average
Your land is one point inside Iron Mountain
Everything above resolves to Iron Mountain as a whole — one PHZM band and one 28°F frost record, read across 5K 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 Iron Mountain Average
Iron Mountain Average
- ●USDA Zones 4b, averaged across Iron Mountain
- ●One soil character for all of Iron Mountain
- ●Frost dates read at Iron Mountain's scale: May 12 to Oct 7
YOUR Parcel
- ✓Your exact zone, not Iron Mountain's 4b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Iron Mountain
Pull a site-specific report for your exact address in Iron Mountain, Michigan — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Iron Mountain averages can't show:
We read public map data around Iron Mountain — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Iron Mountain average
How we know this about Iron Mountain
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 Iron Mountain’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 Iron Mountain
When does frost risk typically end in Iron Mountain?
The last hard freeze (28°F) in Iron Mountain typically lands around May 12, 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 2.
When is the first frost in Iron Mountain?
The first hard freeze (28°F) in Iron Mountain typically arrives around Oct 7, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 23, so the watching starts about Sep 7 — about 148 days after the spring freeze cleared.
How long is the growing season in Iron Mountain?
Measured between 28°F hard freezes, Iron Mountain sees about 148 frost-free days — roughly May 12 through Oct 7, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 2 to Sep 23, about 113 days.
Is the soil safe to grow vegetables in Iron Mountain?
The federal record around Iron Mountain is a meaningful one — 392 documented sites, mostly Underground Storage Tanks entries (178), the nearest Underground Storage Tanks record about 0.1 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 Iron Mountain?
With about 148 frost-free days between hard freezes, Iron Mountain 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 176 to 204 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 12 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Iron Mountain's scale — its 4b band and its 148-day season. Your yard writes its own version of Iron Mountain'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 Iron Mountain’s own scale
6 of the readings below were taken at Iron Mountain's own scale — its own ~148-day season between 28°F freezes, the 4,827 acres it covers and 392 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Iron Mountain's own USDA hardiness band, zones 4bUSDA PHZM 2023
- Iron Mountain's own 28°F hard-freeze dates, about May 12 and Oct 7 and the ~148-day span between themNOAA 1991–2020 Climate Normals
- 392 documented contamination sites on the federal record near Iron Mountain, the closest Underground Storage Tanks record about 0.1 miles out from the town centreFederal environmental registers
- Iron Mountain's boundary and the 4,827 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4b and a ~148-day seasonGrowable Ground crop-matching engine
- The ecoregion at Iron Mountain's own centroid, the Northern Lakes and ForestsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Iron Mountain's 4,827 acres read through its county's SSURGO summaryfrom Dickinson County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Dickinson County
- The growing challenges every Michigan grower plans around — written at state scale, so they stay on the state guidefrom Michigan
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Dickinson County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Iron Mountain's 4,827 acreswhy one lot differs from the next →
- Which side of Iron Mountain you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 4,827 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.1 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 Iron Mountain-wide figureread your own land →
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