Dayton, 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.
The conditions favor cabbage, cranberry, lavender, and collard greens, among others — though every individual site edits that list with its own soil, sun, and drainage.
Even in Dayton, 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 Dayton 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 Dayton — soil, climate, flood, and parcel records. How we handle your address.
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Dayton — the short answer
Dayton, Iowa: USDA zone 5a, about 190 days between hard freezes, across 545 acres of city.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 14
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 21
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~190
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 545 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 Dayton's average, not your lot's — a low corner or a tree line moves it. Against Dayton's 190-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Dayton
Each reading below is measured for Dayton itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredDayton 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
MeasuredDayton 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 Dayton is in
Dayton sits in the Western Corn Belt Plains — EPA Level III, inside the wider Great Plains. That is read at Dayton's own centroid rather than borrowed from Webster County.
What Grows in Dayton
Every plant below cleared Dayton's own zone 5a and its 190-day season. Each card opens that plant's Iowa profile. How we score.
Is it too late to plant in Dayton?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Mar 17; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 14 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 21 — 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 Dayton
Closest first, within ~10 miles of Dayton. Listing isn't leaking, and distance isn't exposure.
- DAYTON COMMUNITY SCHOOLUnderground Storage Tanks · 150 ft
- GENE MOELLER OIL COUnderground Storage Tanks · 250 ft
- DAYTON OIL COMPANYUnderground Storage Tanks · 500 ft
- 086N28W14ADAB 1931Dayton 2Nitrate · 700 ft
- CASEY''S GENERAL STORE 2515Underground Storage Tanks · 850 ft
- DAYTON GOLF & COUNTRY CLUBUnderground Storage Tanks · 900 ft
- EDDIE GRETTENBERGUnderground Storage Tanks · 900 ft
- WEBSTER CO. DAYTON SHOPUnderground Storage Tanks · 1100 ft
- CASEY''S GENERAL STORE #1001Underground Storage Tanks · 1100 ft
- CITY OF DAYTONUnderground Storage Tanks · 1500 ft
- 086N28W14ADBA 05548 1952Dayton 3Nitrate · 1700 ft
- HY-CAPACITY ENG & MFG INCBrownfields · 0.5 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Dayton'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 Dayton.
Sources Checked
within ~10 miles of Dayton
Severity Distribution
within ~10 miles of Dayton
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Dayton, Nitrate runs higher than the national average — 32 sites within ~10 miles of Dayton. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Dayton
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 Dayton average
Your land is one point inside Dayton
Everything above resolves to Dayton as a whole — one PHZM band and one 28°F frost record, read across 545 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 Dayton Average
Dayton Average
- ●USDA Zones 5a, averaged across Dayton
- ●One soil character for all of Dayton
- ●Frost dates read at Dayton's scale: Apr 14 to Oct 21
YOUR Parcel
- ✓Your exact zone, not Dayton's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Dayton
Pull a site-specific report for your exact address in Dayton, Iowa — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Dayton averages can't show:
We read public map data around Dayton — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Dayton average
How we know this about Dayton
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 Dayton’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 Dayton
When does frost risk typically end in Dayton?
The last hard freeze (28°F) in Dayton typically lands around Apr 14, 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 5.
When is the first frost in Dayton?
The first hard freeze (28°F) in Dayton typically arrives around Oct 21, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 7, so the watching starts about Sep 21 — about 190 days after the spring freeze cleared.
How long is the growing season in Dayton?
Measured between 28°F hard freezes, Dayton sees about 190 frost-free days — roughly Apr 14 through Oct 21, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 5 to Oct 7, about 155 days.
Is the soil safe to grow vegetables in Dayton?
The federal record around Dayton shows 68 documented sites, mostly Nitrate entries (32), 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 Dayton?
From about Sep 21 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 21 (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 21. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Dayton's scale — its 5a band and its 190-day season. Your yard writes its own version of Dayton'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 Dayton’s own scale
6 of the readings below were taken at Dayton's own scale — its own ~190-day season between 28°F freezes, the 545 acres it covers and 68 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Dayton's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Dayton's own 28°F hard-freeze dates, about Apr 14 and Oct 21 and the ~190-day span between themNOAA 1991–2020 Climate Normals
- 68 documented contamination sites on the federal record near Dayton, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- Dayton's boundary and the 545 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~190-day seasonGrowable Ground crop-matching engine
- The ecoregion at Dayton'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 Dayton's 545 acres read through its county's SSURGO summaryfrom Webster County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Webster 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 Webster County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Dayton's 545 acreswhy one lot differs from the next →
- Which side of Dayton you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 545 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 Dayton-wide figureread your own land →
More in Iowa
Wider growing context
What grows across IowaDayton sits outside our named growing regions, so Iowa as a whole is its closest context here.
Nearby growing guides