Marne, Iowa, sits in USDA hardiness zone 5b — a zone band wide enough that plant choice, not possibility, is the interesting question.
Among the crops suited to this profile: cabbage, cranberry, lavender, and collard greens. The site-level story — soil, sun, drainage — decides the rest.
Even in Marne, 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 Marne 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 Marne — soil, climate, flood, and parcel records. How we handle your address.
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Marne — the short answer
Marne, Iowa: USDA zone 5b, about 190 days between hard freezes, across 359 acres of city.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 12
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 19
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~190
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 359 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 5b is Marne's average, not your lot's — a low corner or a tree line moves it. Against Marne's 190-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Marne
Each reading below is measured for Marne itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredMarne runs about 190 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
MeasuredMarne sits in USDA hardiness zone 5b.
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 Marne is in
Marne sits in the Western Corn Belt Plains — EPA Level III, inside the wider Great Plains. That is read at Marne's own centroid rather than borrowed from Cass County.
What Grows in Marne
Every plant below cleared Marne's own zone 5b and its 190-day season. Each card opens that plant's Iowa profile. How we score.
Is it too late to plant in Marne?
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 Mar 15; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 12 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 19 — 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 Marne
Closest first, within ~10 miles of Marne. Listing isn't leaking, and distance isn't exposure.
- ATLANTIC MUNICIPAL UTILITIESPFAS · 2.6 mi
- JAMES S COMES FARMUnderground Storage Tanks · 2.8 mi
- ROBINSON FARMCAFO · 2.8 mi
- HUBBARD FEEDSUnderground Storage Tanks · 4.5 mi
- HUBBARD FEEDS INCToxics Release Inventory · 4.6 mi
- ELITE OCTANE, LLCToxics Release Inventory · 4.6 mi
- ELITE OCTANE, LLCBrownfields · 4.6 mi
- GLACIER VANDERVELL INCORPORATEDToxics Release Inventory · 4.6 mi
- GLACIER VANDERVELL INCORPORATEDBrownfields · 4.6 mi
- WPCDUnderground Storage Tanks · 5.1 mi
- ATLANTIC MUNICIPAL AIRPORTUnderground Storage Tanks · 5.1 mi
- CASEY''S GENERAL STORE 2365Underground Storage Tanks · 5.4 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Marne'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 Marne.
Sources Checked
within ~10 miles of Marne
Severity Distribution
within ~10 miles of Marne
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Marne, two things run higher than the national average within ~10 miles of Marne — CAFO (4 sites) and Underground Storage Tanks (85 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
CAFO: CAFOs pose a different contamination profile than chemical sources.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Marne
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 Marne average
Your land is one point inside Marne
Everything above resolves to Marne as a whole — one PHZM band and one 28°F frost record, read across 359 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 Marne Average
Marne Average
- ●USDA Zones 5b, averaged across Marne
- ●One soil character for all of Marne
- ●Frost dates read at Marne's scale: Apr 12 to Oct 19
YOUR Parcel
- ✓Your exact zone, not Marne's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Marne
Pull a site-specific report for your exact address in Marne, Iowa — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Marne averages can't show:
We read public map data around Marne — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Marne average
How we know this about Marne
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 Marne’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 Marne
When does frost risk typically end in Marne?
The last hard freeze (28°F) in Marne typically lands around Apr 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 May 3.
When is the first frost in Marne?
The first hard freeze (28°F) in Marne typically arrives around Oct 19, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 5, so the watching starts about Sep 19 — about 190 days after the spring freeze cleared.
How long is the growing season in Marne?
Measured between 28°F hard freezes, Marne sees about 190 frost-free days — roughly Apr 12 through Oct 19, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 3 to Oct 5, about 155 days.
Is the soil safe to grow vegetables in Marne?
The federal record around Marne is a meaningful one — 132 documented sites, mostly Underground Storage Tanks entries (85), the nearest PFAS record about 2.6 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 Marne?
From about Sep 19 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 19 (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 19. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Marne's scale — its 5b band and its 190-day season. Your yard writes its own version of Marne'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 Marne’s own scale
6 of the readings below were taken at Marne's own scale — its own ~190-day season between 28°F freezes, the 359 acres it covers and 132 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Marne's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Marne's own 28°F hard-freeze dates, about Apr 12 and Oct 19 and the ~190-day span between themNOAA 1991–2020 Climate Normals
- 132 documented contamination sites on the federal record near Marne, the closest PFAS record about 2.6 miles out from the town centreFederal environmental registers
- Marne's boundary and the 359 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~190-day seasonGrowable Ground crop-matching engine
- The ecoregion at Marne's own centroid, the Western Corn Belt PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Marne's 359 acres read through its county's SSURGO summaryfrom Cass County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Cass County
- The growing challenges every Iowa grower plans around — written at state scale, so they stay on the state guidefrom Iowa
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Cass County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Marne's 359 acreswhy one lot differs from the next →
- Which side of Marne you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 359 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest PFAS record about 2.6 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 Marne-wide figureread your own land →
More in Iowa
Wider growing context
What grows across IowaMarne sits outside our named growing regions, so Iowa as a whole is its closest context here.