Cincinnati, 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.
Crops well matched to these conditions include cabbage, cranberry, lavender, and collard greens — though what thrives on any one site still turns on its specific soil, sun, and drainage.
Even in Cincinnati, 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 Cincinnati 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 Cincinnati — soil, climate, flood, and parcel records. How we handle your address.
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Cincinnati — the short answer
Cincinnati, Iowa: USDA zone 5b, about 201 days between hard freezes, across 1K acres of city.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 8
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 26
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~201
- 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 Cincinnati's average, not your lot's — a low corner or a tree line moves it. Against Cincinnati's 201-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Cincinnati
Each reading below is measured for Cincinnati itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredCincinnati runs about 201 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
MeasuredCincinnati 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 Cincinnati is in
Cincinnati sits in the Central Irregular Plains — EPA Level III, inside the wider Great Plains. That is read at Cincinnati's own centroid rather than borrowed from Appanoose County.
What Grows in Cincinnati
Every plant below cleared Cincinnati's own zone 5b and its 201-day season. Each card opens that plant's Iowa profile. How we score.
Is it too late to plant in Cincinnati?
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 11; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 8 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 26 — long-season crops need about 90 days of runway, quick greens only 30. Here the season winds down slowly: late sowings, a real autumn harvest, and garlic in the ground before the first hard freeze.
What's on the federal record near Cincinnati
Closest first, within ~10 miles of Cincinnati. Listing isn't leaking, and distance isn't exposure.
- WEST GROCERYUnderground Storage Tanks · 650 ft
- KONVENIENCE KORNERUnderground Storage Tanks · 700 ft
- 067N18W03BCAC 00976 1939CincinnatiNitrate · 850 ft
- STEVEN C MORIARTYUnderground Storage Tanks · 1500 ft
- 067N18W03CBBC 19808 1967Cincinnati 1Nitrate · 2300 ft
- 067N24W13AAB 1966Nitrate · 1.2 mi
- CENTERVILLE MUNICIPAL AIRPORTUnderground Storage Tanks · 4.4 mi
- FINE OIL CO INCUnderground Storage Tanks · 4.4 mi
- EXLINE OLD COUNTRY STORE & ANTIQUESUnderground Storage Tanks · 4.4 mi
- 068N18W14BAAA 1935Nitrate · 4.5 mi
- T67N R19W 25DBC1Nitrate · 5.0 mi
- T67N R19W 25CBB1Nitrate · 5.0 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Cincinnati'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 Cincinnati.
Total Sites
100
within ~10 miles of Cincinnati
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Cincinnati
Severity Distribution
within ~10 miles of Cincinnati
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Cincinnati, two things run higher than the national average within ~10 miles of Cincinnati — CAFO (4 sites) and Toxics Release Inventory (8 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
CAFO: CAFOs pose a different contamination profile than chemical sources.
Toxics Release Inventory: TRI facilities report annual chemical releases to air, water, and land.
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Check your specific parcel in Cincinnati
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 Cincinnati average
Your land is one point inside Cincinnati
Everything above resolves to Cincinnati 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 Cincinnati Average
Cincinnati Average
- ●USDA Zones 5b, averaged across Cincinnati
- ●One soil character for all of Cincinnati
- ●Frost dates read at Cincinnati's scale: Apr 8 to Oct 26
YOUR Parcel
- ✓Your exact zone, not Cincinnati's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Cincinnati
Pull a site-specific report for your exact address in Cincinnati, Iowa — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Cincinnati averages can't show:
We read public map data around Cincinnati — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Cincinnati average
How we know this about Cincinnati
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 Cincinnati’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 Cincinnati
When does frost risk typically end in Cincinnati?
The last hard freeze (28°F) in Cincinnati typically lands around Apr 8, 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 29.
When is the first frost in Cincinnati?
The first hard freeze (28°F) in Cincinnati typically arrives around Oct 26, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 12, so the watching starts about Sep 26 — about 201 days after the spring freeze cleared.
How long is the growing season in Cincinnati?
Measured between 28°F hard freezes, Cincinnati sees about 201 frost-free days — roughly Apr 8 through Oct 26, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 29 to Oct 12, about 166 days.
Is the soil safe to grow vegetables in Cincinnati?
The federal record around Cincinnati is a meaningful one — 100 documented sites, mostly Underground Storage Tanks entries (48), 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 Cincinnati?
From about Sep 26 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 26 (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 26. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Cincinnati's scale — its 5b band and its 201-day season. Your yard writes its own version of Cincinnati'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 Cincinnati’s own scale
6 of the readings below were taken at Cincinnati's own scale — its own ~201-day season between 28°F freezes, the 1,124 acres it covers and 100 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Cincinnati's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Cincinnati's own 28°F hard-freeze dates, about Apr 8 and Oct 26 and the ~201-day span between themNOAA 1991–2020 Climate Normals
- 100 documented contamination sites on the federal record near Cincinnati, the closest Underground Storage Tanks record about 0.1 miles out from the town centreFederal environmental registers
- Cincinnati's boundary and the 1,124 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~201-day seasonGrowable Ground crop-matching engine
- The ecoregion at Cincinnati's own centroid, the Central Irregular PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Cincinnati's 1,124 acres read through its county's SSURGO summaryfrom Appanoose County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Appanoose 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 Appanoose County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Cincinnati's 1,124 acreswhy one lot differs from the next →
- Which side of Cincinnati you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,124 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 Cincinnati-wide figureread your own land →
More in Iowa
Wider growing context
What grows across IowaCincinnati sits outside our named growing regions, so Iowa as a whole is its closest context here.
Nearby growing guides