Iron River, Michigan, sits in USDA hardiness zone 4a — a zone band wide enough that plant choice, not possibility, is the interesting question.
Expect cabbage, cranberry, cilantro, and collard greens to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
Even in Iron River, 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 River 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 River — soil, climate, flood, and parcel records. How we handle your address.
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Iron River — the short answer
Iron River, Michigan: USDA zone 4a, about 124 days between hard freezes, across 4K acres of city.
- USDA zone
- 4a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 24
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Sep 25
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~124
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 4K 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 Iron River's average, not your lot's — a low corner or a tree line moves it. Against Iron River's 124-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Iron River
Each reading below is measured for Iron River itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredIron River runs about 124 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 River 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 Iron River is in
Iron River sits in the Northern Lakes and Forests — EPA Level III, inside the wider Northern Forests. That is read at Iron River's own centroid rather than borrowed from Iron County.
What Grows in Iron River
Every plant below cleared Iron River's own zone 4a and its 124-day season. Each card opens that plant's Michigan profile. How we score.
Is it too late to plant in Iron River?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Apr 26; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 24 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Sep 25 — long-season crops need about 90 days of runway, quick greens only 30. In a season this compact, fast finishers and cold-hardy greens do the late work, and garlic tucked in before the freeze repays you next summer.
What's on the federal record near Iron River
Closest first, within ~10 miles of Iron River. Listing isn't leaking, and distance isn't exposure.
- MI DEPT/MILITARY & VETERANS AFFAIRSBrownfields · 1100 ft
- West Iron County Public SchoolsUnderground Storage Tanks · 1300 ft
- Holiday Stationstore #152Underground Storage Tanks · 1400 ft
- Krist Food Mart #8Underground Storage Tanks · 1400 ft
- COMMERCIAL BUILDINGBrownfields · 1500 ft
- Iron River BP #38Underground Storage Tanks · 1600 ft
- RAINBOW DRY CLEANERSBrownfields · 1600 ft
- Hoover's StandardUnderground Storage Tanks · 1800 ft
- Riverside 76Underground Storage Tanks · 1900 ft
- VacantUnderground Storage Tanks · 2000 ft
- APC STORES INCBrownfields · 2000 ft
- Wyatt's AutomotiveUnderground Storage Tanks · 2100 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Iron River'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 River.
Total Sites
72
within ~10 miles of Iron River
Risk Level
Moderate
Highest-severity
1 Toxics Release Inventory facility
Sources Checked
within ~10 miles of Iron River
Severity Distribution
within ~10 miles of Iron River
Highest-Severity Sites
Know Before You Grow
- •Underground tanks leak petroleum as they age — near a former filling station, test the soil.
- •Near a brownfield, raised beds of imported soil give your food clean ground.
- •On a private well, test for nitrates: above 10 mg/L the water needs treatment before irrigating.
Check your specific parcel in Iron River
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 River average
Your land is one point inside Iron River
Everything above resolves to Iron River as a whole — one PHZM band and one 28°F frost record, read across 4K 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 River Average
Iron River Average
- ●USDA Zones 4a, averaged across Iron River
- ●One soil character for all of Iron River
- ●Frost dates read at Iron River's scale: May 24 to Sep 25
YOUR Parcel
- ✓Your exact zone, not Iron River's 4a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Iron River
Pull a site-specific report for your exact address in Iron River, Michigan — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Iron River averages can't show:
We read public map data around Iron River — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Iron River average
How we know this about Iron River
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 River’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 River
When does frost risk typically end in Iron River?
The last hard freeze (28°F) in Iron River typically lands around May 24, 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 14.
When is the first frost in Iron River?
The first hard freeze (28°F) in Iron River typically arrives around Sep 25, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 11, so the watching starts about Aug 26 — about 124 days after the spring freeze cleared.
How long is the growing season in Iron River?
Measured between 28°F hard freezes, Iron River sees about 124 frost-free days — roughly May 24 through Sep 25, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 14 to Sep 11, about 89 days.
Is the soil safe to grow vegetables in Iron River?
The federal record around Iron River shows 72 documented sites, mostly Underground Storage Tanks entries (40), the nearest Brownfields record about 0.2 miles out — a typical footprint for a growing area, and proximity to a documented site is information, not a diagnosis of any one yard. It's worth seeing which recorded sites sit closest to where you grow, and testing the soil before new food beds near any of them.
How do gardeners stretch the season in Iron River?
With about 124 frost-free days between hard freezes, Iron River 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 152 to 180 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 24 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Iron River's scale — its 4a band and its 124-day season. Your yard writes its own version of Iron River'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 River’s own scale
6 of the readings below were taken at Iron River's own scale — its own ~124-day season between 28°F freezes, the 4,311 acres it covers and 72 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Iron River's own USDA hardiness band, zones 4aUSDA PHZM 2023
- Iron River's own 28°F hard-freeze dates, about May 24 and Sep 25 and the ~124-day span between themNOAA 1991–2020 Climate Normals
- 72 documented contamination sites on the federal record near Iron River, the closest Brownfields record about 0.2 miles out from the town centreFederal environmental registers
- Iron River's boundary and the 4,311 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4a and a ~124-day seasonGrowable Ground crop-matching engine
- The ecoregion at Iron River'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 River's 4,311 acres read through its county's SSURGO summaryfrom Iron County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Iron 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 Iron County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Iron River's 4,311 acreswhy one lot differs from the next →
- Which side of Iron River you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 4,311 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields 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 Iron River-wide figureread your own land →
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