Wilton, Iowa, sits in USDA hardiness zone 5b — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
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 Wilton, 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 Wilton 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 Wilton — soil, climate, flood, and parcel records. How we handle your address.
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Wilton — the short answer
Wilton, Iowa: USDA zone 5b, about 204 days between hard freezes, across 1K acres of city.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 6
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 27
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~204
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 1K 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 Wilton's average, not your lot's — a low corner or a tree line moves it. Against Wilton's 204-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Wilton
Each reading below is measured for Wilton itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredWilton runs about 204 days between hard freezes — a long growing season.
There is slack for succession plantings and slow-finishing crops: many vegetables can be sown twice, and the heat-lovers have time to ripen fully.
Plan a second sowing of quick crops after the first comes out, and use the fall window most gardeners let sit idle.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredWilton 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 Wilton is in
Wilton sits in the Western Corn Belt Plains — EPA Level III, inside the wider Great Plains. That is read at Wilton's own centroid rather than borrowed from Muscatine County.
What Grows in Wilton
Every plant below cleared Wilton's own zone 5b and its 204-day season. Each card opens that plant's Iowa profile. How we score.
Is it too late to plant in Wilton?
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 9; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 6 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 27 — long-season crops need about 90 days of runway, quick greens only 30. There is slack in a calendar like this — late plantings, second rounds of favorites, and a fall bench that keeps beds working.
What's on the federal record near Wilton
Closest first, within ~10 miles of Wilton. Listing isn't leaking, and distance isn't exposure.
- CASEY''S GENERAL STORE 61Underground Storage Tanks · 350 ft
- COUNTY MAINTENANCE SHOPUnderground Storage Tanks · 500 ft
- VALETS SERVICEUnderground Storage Tanks · 500 ft
- Not KnownUnderground Storage Tanks · 750 ft
- GEURINK SON FEED & SUPPLYUnderground Storage Tanks · 800 ft
- HON COBrownfields · 1200 ft
- HON COToxics Release Inventory · 1200 ft
- J R REFUELUnderground Storage Tanks · 1600 ft
- HAROLD ""BILL"" GRUNDER & SONS INCUnderground Storage Tanks · 1600 ft
- FORMER CROP MATE COMPANYUnderground Storage Tanks · 1600 ft
- WILTON MUNICIPAL LIGHT & POWERUnderground Storage Tanks · 1800 ft
- FORMER STEFFEN''S FS SERVICEUnderground Storage Tanks · 1800 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Wilton'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 Wilton.
Total Sites
131
within ~10 miles of Wilton
Risk Level
Moderate
Highest-severity
12 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Wilton
Severity Distribution
within ~10 miles of Wilton
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Wilton, Toxics Release Inventory runs higher than the national average — 12 sites within ~10 miles of Wilton. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Toxics Release Inventory: TRI facilities report annual chemical releases to air, water, and land.
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Check your specific parcel in Wilton
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 Wilton average
Your land is one point inside Wilton
Everything above resolves to Wilton as a whole — one PHZM band and one 28°F frost record, read across 1K 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 Wilton Average
Wilton Average
- ●USDA Zones 5b, averaged across Wilton
- ●One soil character for all of Wilton
- ●Frost dates read at Wilton's scale: Apr 6 to Oct 27
YOUR Parcel
- ✓Your exact zone, not Wilton's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Wilton
Pull a site-specific report for your exact address in Wilton, Iowa — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Wilton averages can't show:
We read public map data around Wilton — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Wilton average
How we know this about Wilton
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 Wilton’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 Wilton
When does frost risk typically end in Wilton?
The last hard freeze (28°F) in Wilton typically lands around Apr 6, 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 Apr 27.
When is the first frost in Wilton?
The first hard freeze (28°F) in Wilton typically arrives around Oct 27, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 13, so the watching starts about Sep 27 — about 204 days after the spring freeze cleared.
How long is the growing season in Wilton?
Measured between 28°F hard freezes, Wilton sees about 204 frost-free days — roughly Apr 6 through Oct 27, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 27 to Oct 13, about 169 days.
Is the soil safe to grow vegetables in Wilton?
The federal record around Wilton shows 131 documented sites, mostly Underground Storage Tanks entries (66), the nearest Underground Storage Tanks record under a tenth of a mile 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 I protect my plants from frost in Wilton?
From about Sep 27 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 27 (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 27. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Wilton's scale — its 5b band and its 204-day season. Your yard writes its own version of Wilton'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 Wilton’s own scale
6 of the readings below were taken at Wilton's own scale — its own ~204-day season between 28°F freezes, the 1,315 acres it covers and 131 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Wilton's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Wilton's own 28°F hard-freeze dates, about Apr 6 and Oct 27 and the ~204-day span between themNOAA 1991–2020 Climate Normals
- 131 documented contamination sites on the federal record near Wilton, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- Wilton's boundary and the 1,315 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~204-day seasonGrowable Ground crop-matching engine
- The ecoregion at Wilton'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 Wilton's 1,315 acres read through its county's SSURGO summaryfrom Muscatine County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Muscatine 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 Muscatine County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Wilton's 1,315 acreswhy one lot differs from the next →
- Which side of Wilton you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,315 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 Wilton-wide figureread your own land →
More in Iowa
Wider growing context
What grows across IowaWilton sits outside our named growing regions, so Iowa as a whole is its closest context here.
Nearby growing guides