Ashton, Iowa, sits in USDA hardiness zone 5a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
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 Ashton, 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 Ashton 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 Ashton — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Ashton — the short answer
Ashton, Iowa: USDA zone 5a, about 176 days between hard freezes, across 716 acres of city.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 20
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 13
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~176
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 716 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 Ashton's average, not your lot's — a low corner or a tree line moves it. Against Ashton's 176-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Ashton
Each reading below is measured for Ashton itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredAshton runs about 176 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
MeasuredAshton 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 Ashton is in
Ashton sits in the Western Corn Belt Plains — EPA Level III, inside the wider Great Plains. That is read at Ashton's own centroid rather than borrowed from Osceola County.
What Grows in Ashton
Every plant below cleared Ashton's own zone 5a and its 176-day season. Each card opens that plant's Iowa profile. How we score.
Is it too late to plant in Ashton?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Mar 23; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 20 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 13 — long-season crops need about 90 days of runway, quick greens only 30. Late in the year the fall bench takes over — quick greens, radishes, and garlic that repays you next summer.
What's on the federal record near Ashton
Closest first, within ~10 miles of Ashton. Listing isn't leaking, and distance isn't exposure.
- FRONTIER COMMUNICATIONSUnderground Storage Tanks · 750 ft
- ASHTON MOTOR COUnderground Storage Tanks · 850 ft
- COOPERATIVE ENERGY COMPANYUnderground Storage Tanks · 850 ft
- 098N42W15BDDB 1940Ashton 2Nitrate · 950 ft
- 098N42W15ACBB Ashton 1Nitrate · 950 ft
- COUNTY ENGINEERS OFFICEUnderground Storage Tanks · 1100 ft
- Not KnownUnderground Storage Tanks · 1200 ft
- IMHOFF OIL COUnderground Storage Tanks · 1300 ft
- OSCEOLA COUNTY COOP OIL COUnderground Storage Tanks · 1700 ft
- IOWA DEPARTMENT OF TRANSPORTATIONBrownfields · 2000 ft
- POET BIOREFINING - ASHTON LLCToxics Release Inventory · 2.4 mi
- 098N42W33AABB 25900 1980IGS CRET Proj D-40 (Deep)Nitrate · 2.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Ashton'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 Ashton.
Total Sites
165
within ~10 miles of Ashton
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Ashton
Severity Distribution
within ~10 miles of Ashton
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Ashton, two things run higher than the national average within ~10 miles of Ashton — CAFO (3 sites) and Nitrate (50 sites). That's not a problem with your land — it's information about it.
CAFO: CAFOs pose a different contamination profile than chemical sources.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Ashton
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 Ashton average
Your land is one point inside Ashton
Everything above resolves to Ashton as a whole — one PHZM band and one 28°F frost record, read across 716 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 Ashton Average
Ashton Average
- ●USDA Zones 5a, averaged across Ashton
- ●One soil character for all of Ashton
- ●Frost dates read at Ashton's scale: Apr 20 to Oct 13
YOUR Parcel
- ✓Your exact zone, not Ashton's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Ashton
Pull a site-specific report for your exact address in Ashton, Iowa — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Ashton averages can't show:
We read public map data around Ashton — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Ashton average
How we know this about Ashton
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 Ashton’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 Ashton
When does frost risk typically end in Ashton?
The last hard freeze (28°F) in Ashton typically lands around Apr 20, 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 11.
When is the first frost in Ashton?
The first hard freeze (28°F) in Ashton typically arrives around Oct 13, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 29, so the watching starts about Sep 13 — about 176 days after the spring freeze cleared.
How long is the growing season in Ashton?
Measured between 28°F hard freezes, Ashton sees about 176 frost-free days — roughly Apr 20 through Oct 13, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 11 to Sep 29, about 141 days.
Is the soil safe to grow vegetables in Ashton?
The federal record around Ashton is a meaningful one — 165 documented sites, mostly Underground Storage Tanks entries (75), the nearest Underground Storage Tanks record about 0.1 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 Ashton?
From about Sep 13 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 13 (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 13. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Ashton's scale — its 5a band and its 176-day season. Your yard writes its own version of Ashton'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 Ashton’s own scale
6 of the readings below were taken at Ashton's own scale — its own ~176-day season between 28°F freezes, the 716 acres it covers and 165 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Ashton's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Ashton's own 28°F hard-freeze dates, about Apr 20 and Oct 13 and the ~176-day span between themNOAA 1991–2020 Climate Normals
- 165 documented contamination sites on the federal record near Ashton, the closest Underground Storage Tanks record about 0.1 miles out from the town centreFederal environmental registers
- Ashton's boundary and the 716 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~176-day seasonGrowable Ground crop-matching engine
- The ecoregion at Ashton'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 Ashton's 716 acres read through its county's SSURGO summaryfrom Osceola County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Osceola 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 Osceola County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Ashton's 716 acreswhy one lot differs from the next →
- Which side of Ashton you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 716 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.1 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 Ashton-wide figureread your own land →
More in Iowa
Wider growing context
What grows across IowaAshton sits outside our named growing regions, so Iowa as a whole is its closest context here.
Nearby growing guides