Marengo, Wisconsin, sits in USDA hardiness zone 4b — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
On paper, cabbage, cranberry, turkish rocket, and collard greens all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Even in Marengo, 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 Marengo 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 Marengo — soil, climate, flood, and parcel records. How we handle your address.
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Marengo — the short answer
Marengo, Wisconsin: USDA zone 4b, about 153 days between hard freezes, across 669 acres of town.
- USDA zone
- 4b
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 9
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 9
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~153
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 669 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 Marengo's average, not your lot's — a low corner or a tree line moves it. Against Marengo's 153-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Marengo
Each reading below is measured for Marengo itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredMarengo runs about 153 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
MeasuredMarengo 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 Marengo is in
Marengo sits in the Northern Lakes and Forests — EPA Level III, inside the wider Northern Forests. That is read at Marengo's own centroid rather than borrowed from Ashland County.
What Grows in Marengo
Every plant below cleared Marengo's own zone 4b and its 153-day season. Each card opens that plant's Wisconsin profile. How we score.
Is it too late to plant in Marengo?
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 11; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 9 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 9 — 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 Marengo
Closest first, within ~10 miles of Marengo. Listing isn't leaking, and distance isn't exposure.
- AS-46/04W/36-0100Nitrate · 2300 ft
- Jacks Store IncUnderground Storage Tanks · 2600 ft
- MARENGO OIL COUnderground Storage Tanks · 2600 ft
- AS-46/03W/29-0222Nitrate · 2.2 mi
- TOWN OF MARENGO GARAGEUnderground Storage Tanks · 2.3 mi
- AS-46/03W/20-0221Nitrate · 2.5 mi
- AS-46/04W/22-0070Nitrate · 2.9 mi
- AS-46/03W/33-0223Nitrate · 3.3 mi
- AS-46/04W/11-0071Nitrate · 3.8 mi
- DANS MOBILUnderground Storage Tanks · 4.1 mi
- Theresa HunterUnderground Storage Tanks · 4.1 mi
- ASHLAND COUNTY HWY DEPTUnderground Storage Tanks · 4.1 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Marengo'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 Marengo.
Total Sites
65
within ~10 miles of Marengo
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Marengo
Severity Distribution
within ~10 miles of Marengo
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Marengo, Nitrate runs higher than the national average — 22 sites within ~10 miles of Marengo. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Marengo
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 Marengo average
Your land is one point inside Marengo
Everything above resolves to Marengo as a whole — one PHZM band and one 28°F frost record, read across 669 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 Marengo Average
Marengo Average
- ●USDA Zones 4b, averaged across Marengo
- ●One soil character for all of Marengo
- ●Frost dates read at Marengo's scale: May 9 to Oct 9
YOUR Parcel
- ✓Your exact zone, not Marengo's 4b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Marengo
Pull a site-specific report for your exact address in Marengo, Wisconsin — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Marengo averages can't show:
We read public map data around Marengo — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Marengo average
How we know this about Marengo
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 Marengo’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 Marengo
When does frost risk typically end in Marengo?
The last hard freeze (28°F) in Marengo typically lands around May 9, 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 30.
When is the first frost in Marengo?
The first hard freeze (28°F) in Marengo typically arrives around Oct 9, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 25, so the watching starts about Sep 9 — about 153 days after the spring freeze cleared.
How long is the growing season in Marengo?
Measured between 28°F hard freezes, Marengo sees about 153 frost-free days — roughly May 9 through Oct 9, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 30 to Sep 25, about 118 days.
Is the soil safe to grow vegetables in Marengo?
The federal record around Marengo is a meaningful one — 65 documented sites, mostly Underground Storage Tanks entries (32), the nearest Nitrate record about 0.4 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 Marengo?
From about Sep 9 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 9 (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 9. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Marengo's scale — its 4b band and its 153-day season. Your yard writes its own version of Marengo'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 Marengo’s own scale
6 of the readings below were taken at Marengo's own scale — its own ~153-day season between 28°F freezes, the 669 acres it covers and 65 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Marengo's own USDA hardiness band, zones 4bUSDA PHZM 2023
- Marengo's own 28°F hard-freeze dates, about May 9 and Oct 9 and the ~153-day span between themNOAA 1991–2020 Climate Normals
- 65 documented contamination sites on the federal record near Marengo, the closest Nitrate record about 0.4 miles out from the town centreFederal environmental registers
- Marengo's boundary and the 669 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4b and a ~153-day seasonGrowable Ground crop-matching engine
- The ecoregion at Marengo'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 Marengo's 669 acres read through its county's SSURGO summaryfrom Ashland County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Ashland County
- The growing challenges every Wisconsin grower plans around — written at state scale, so they stay on the state guidefrom Wisconsin
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Ashland County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Marengo's 669 acreswhy one lot differs from the next →
- Which side of Marengo you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 669 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate record about 0.4 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 Marengo-wide figureread your own land →
More in Wisconsin
Wider growing context
What grows across WisconsinMarengo sits outside our named growing regions, so Wisconsin as a whole is its closest context here.
Nearby growing guides