Gilman, Iowa, sits in USDA hardiness zone 5a — a zone band wide enough that plant choice, not possibility, is the interesting question.
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 Gilman, 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 Gilman 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 Gilman — soil, climate, flood, and parcel records. How we handle your address.
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Gilman — the short answer
Gilman, Iowa: USDA zone 5a, about 192 days between hard freezes, across 343 acres of city.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 13
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 22
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~192
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 343 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 Gilman's average, not your lot's — a low corner or a tree line moves it. Against Gilman's 192-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Gilman
Each reading below is measured for Gilman itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredGilman runs about 192 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
MeasuredGilman 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 Gilman is in
Gilman sits in the Western Corn Belt Plains — EPA Level III, inside the wider Great Plains. That is read at Gilman's own centroid rather than borrowed from Marshall County.
What Grows in Gilman
Every plant below cleared Gilman's own zone 5a and its 192-day season. Each card opens that plant's Iowa profile. How we score.
Is it too late to plant in Gilman?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Mar 16; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 13 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 22 — long-season crops need about 90 days of runway, quick greens only 30. As the window narrows, the plantings just get faster — fall brassicas, then greens, then garlic to finish.
What's on the federal record near Gilman
Closest first, within ~10 miles of Gilman. Listing isn't leaking, and distance isn't exposure.
- SEMCO SCHOOLSUnderground Storage Tanks · 200 ft
- 082N17W26DDDB 01378 1940Gilman 6 ParkNitrate · 250 ft
- TOM''S TIRE AND AUTO LLCUnderground Storage Tanks · 350 ft
- CITY OF GILMANUnderground Storage Tanks · 350 ft
- THE DEPOT GILMANUnderground Storage Tanks · 650 ft
- ROYCE J FICHTNER PEUnderground Storage Tanks · 700 ft
- TOW SHOPToxics Release Inventory · 1.4 mi
- 082N17W33CCADNitrate · 3.0 mi
- 082N17W12CBB 03592 1949Nitrate · 3.3 mi
- RANDY NEKOLAUnderground Storage Tanks · 3.7 mi
- 082N17W31ADANitrate · 4.1 mi
- 083N17W36CBBBNitrate · 5.3 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Gilman'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 Gilman.
Total Sites
141
within ~10 miles of Gilman
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Gilman
Severity Distribution
within ~10 miles of Gilman
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Gilman, two things run higher than the national average within ~10 miles of Gilman — Toxics Release Inventory (16 sites) and Nitrate (42 sites). That's not a problem with your land — it's information about it.
Toxics Release Inventory: TRI facilities report annual chemical releases to air, water, and land.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Gilman
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 Gilman average
Your land is one point inside Gilman
Everything above resolves to Gilman as a whole — one PHZM band and one 28°F frost record, read across 343 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 Gilman Average
Gilman Average
- ●USDA Zones 5a, averaged across Gilman
- ●One soil character for all of Gilman
- ●Frost dates read at Gilman's scale: Apr 13 to Oct 22
YOUR Parcel
- ✓Your exact zone, not Gilman's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Gilman
Pull a site-specific report for your exact address in Gilman, Iowa — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Gilman averages can't show:
We read public map data around Gilman — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Gilman average
How we know this about Gilman
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 Gilman’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 Gilman
When does frost risk typically end in Gilman?
The last hard freeze (28°F) in Gilman typically lands around Apr 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 May 4.
When is the first frost in Gilman?
The first hard freeze (28°F) in Gilman typically arrives around Oct 22, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 8, so the watching starts about Sep 22 — about 192 days after the spring freeze cleared.
How long is the growing season in Gilman?
Measured between 28°F hard freezes, Gilman sees about 192 frost-free days — roughly Apr 13 through Oct 22, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 4 to Oct 8, about 157 days.
Is the soil safe to grow vegetables in Gilman?
The federal record around Gilman is a meaningful one — 141 documented sites, mostly Underground Storage Tanks entries (67), the nearest Underground Storage Tanks record under a tenth of a mile 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 Gilman?
From about Sep 22 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 22 (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 22. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Gilman's scale — its 5a band and its 192-day season. Your yard writes its own version of Gilman'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 Gilman’s own scale
6 of the readings below were taken at Gilman's own scale — its own ~192-day season between 28°F freezes, the 343 acres it covers and 141 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Gilman's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Gilman's own 28°F hard-freeze dates, about Apr 13 and Oct 22 and the ~192-day span between themNOAA 1991–2020 Climate Normals
- 141 documented contamination sites on the federal record near Gilman, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- Gilman's boundary and the 343 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~192-day seasonGrowable Ground crop-matching engine
- The ecoregion at Gilman'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 Gilman's 343 acres read through its county's SSURGO summaryfrom Marshall County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Marshall 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 Marshall County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Gilman's 343 acreswhy one lot differs from the next →
- Which side of Gilman you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 343 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record under a tenth of a mile 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 Gilman-wide figureread your own land →
More in Iowa
Wider growing context
What grows across IowaGilman sits outside our named growing regions, so Iowa as a whole is its closest context here.