Afton, Iowa, sits in USDA hardiness zone 5b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Reliable performers under these conditions include cabbage, cranberry, lavender, and collard greens; what your own ground favors still comes down to its soil, sun, and drainage.
Even in Afton, 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 Afton 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 Afton — soil, climate, flood, and parcel records. How we handle your address.
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Afton — the short answer
Afton, Iowa: USDA zone 5b, about 194 days between hard freezes, across 644 acres of city.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 11
- 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
- ~194
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 644 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 Afton's average, not your lot's — a low corner or a tree line moves it. Against Afton's 194-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Afton
Each reading below is measured for Afton itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredAfton runs about 194 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
MeasuredAfton 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 Afton is in
Afton sits in the Western Corn Belt Plains — EPA Level III, inside the wider Great Plains. That is read at Afton's own centroid rather than borrowed from Union County.
What Grows in Afton
Every plant below cleared Afton's own zone 5b and its 194-day season. Each card opens that plant's Iowa profile. How we score.
Is it too late to plant in Afton?
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 14; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 11 (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. Even past midsummer there is room for a true fall garden here, and garlic planted near the close carries the momentum into next year.
What's on the federal record near Afton
Closest first, within ~10 miles of Afton. Listing isn't leaking, and distance isn't exposure.
- KUM & GO #230Underground Storage Tanks · 650 ft
- SCHLAPIA INCUnderground Storage Tanks · 650 ft
- FARMERS COOP CO. - AFTON BRANCHToxics Release Inventory · 650 ft
- UNITED FARMERS COOPERATIVEUnderground Storage Tanks · 850 ft
- NWB/ROCUnderground Storage Tanks · 850 ft
- AFTON HIGH SCHOOL BUS BARNUnderground Storage Tanks · 850 ft
- UNION COUNTY SHEDUnderground Storage Tanks · 850 ft
- CASEY''S GENERAL STORE 2626Underground Storage Tanks · 1500 ft
- 072N29W16CBAD 1913Nitrate · 1900 ft
- SMITH CONCRETE PRODUCTSUnderground Storage Tanks · 2300 ft
- LAKESHORE GOLF & COUNTRY CLUBUnderground Storage Tanks · 0.6 mi
- AFTON CARE CENTERUnderground Storage Tanks · 0.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Afton'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 Afton.
Total Sites
106
within ~10 miles of Afton
Risk Level
Moderate
Highest-severity
8 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Afton
Severity Distribution
within ~10 miles of Afton
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Afton, Toxics Release Inventory runs higher than the national average — 8 sites within ~10 miles of Afton. 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.
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Check your specific parcel in Afton
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 Afton average
Your land is one point inside Afton
Everything above resolves to Afton as a whole — one PHZM band and one 28°F frost record, read across 644 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 Afton Average
Afton Average
- ●USDA Zones 5b, averaged across Afton
- ●One soil character for all of Afton
- ●Frost dates read at Afton's scale: Apr 11 to Oct 22
YOUR Parcel
- ✓Your exact zone, not Afton's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Afton
Pull a site-specific report for your exact address in Afton, Iowa — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Afton averages can't show:
We read public map data around Afton — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Afton average
How we know this about Afton
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 Afton’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 Afton
When does frost risk typically end in Afton?
The last hard freeze (28°F) in Afton typically lands around Apr 11, 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 2.
When is the first frost in Afton?
The first hard freeze (28°F) in Afton 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 194 days after the spring freeze cleared.
How long is the growing season in Afton?
Measured between 28°F hard freezes, Afton sees about 194 frost-free days — roughly Apr 11 through Oct 22, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 2 to Oct 8, about 159 days.
Is the soil safe to grow vegetables in Afton?
The federal record around Afton shows 106 documented sites, mostly Underground Storage Tanks entries (58), the nearest Underground Storage Tanks record about 0.1 miles 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 Afton?
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 Afton's scale — its 5b band and its 194-day season. Your yard writes its own version of Afton'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 Afton’s own scale
6 of the readings below were taken at Afton's own scale — its own ~194-day season between 28°F freezes, the 644 acres it covers and 106 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Afton's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Afton's own 28°F hard-freeze dates, about Apr 11 and Oct 22 and the ~194-day span between themNOAA 1991–2020 Climate Normals
- 106 documented contamination sites on the federal record near Afton, the closest Underground Storage Tanks record about 0.1 miles out from the town centreFederal environmental registers
- Afton's boundary and the 644 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~194-day seasonGrowable Ground crop-matching engine
- The ecoregion at Afton'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 Afton's 644 acres read through its county's SSURGO summaryfrom Union County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Union 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 Union County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Afton's 644 acreswhy one lot differs from the next →
- Which side of Afton you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 644 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 Afton-wide figureread your own land →
More in Iowa
Wider growing context
What grows across IowaAfton sits outside our named growing regions, so Iowa as a whole is its closest context here.
Nearby growing guides