Union City, Ohio, sits in USDA hardiness zone 6a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Reliable performers under these conditions include cabbage, hazelnut, lavender, and collard greens; what your own ground favors still comes down to its soil, sun, and drainage.
Even in Union City, 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 Union City 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 Union City — soil, climate, flood, and parcel records. How we handle your address.
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Union City — the short answer
Union City, Ohio: USDA zone 6a, about 205 days between hard freezes, across 588 acres of town.
- USDA zone
- 6a
- 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 30
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~205
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 588 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 6a is Union City's average, not your lot's — a low corner or a tree line moves it. Against Union City's 205-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Union City
Each reading below is measured for Union City itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredUnion City runs about 205 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
MeasuredUnion City sits in USDA hardiness zone 6a.
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 Union City is in
Union City sits in the Eastern Corn Belt Plains — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Union City's own centroid rather than borrowed from Darke County.
What Grows in Union City
Every plant below cleared Union City's own zone 6a and its 205-day season. Each card opens that plant's Ohio profile. How we score.
Is it too late to plant in Union City?
Almost never — the real question is what to plant next. 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 30 — 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.
Documented around Union City
Survey cells within 31 miles of Union City checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 52 miles off. What to watch for.
What's on the federal record near Union City
Closest first, within ~10 miles of Union City. Listing isn't leaking, and distance isn't exposure.
- CAST METALS TECHNOLOGYToxics Release Inventory · 1500 ft
- BARRETT TRANSFER & LEASINGUnderground Storage Tanks · 0.5 mi
- WARREN'S SUNOCOUnderground Storage Tanks · 0.7 mi
- EMPTY BUILDINGUnderground Storage Tanks · 0.8 mi
- C. E. WRIGHT SONS, INC.Underground Storage Tanks · 0.8 mi
- B & B FOODMART LLCUnderground Storage Tanks · 0.9 mi
- CASEY'S GENERAL STOREUnderground Storage Tanks · 0.9 mi
- DBA RITE AID 4986Brownfields · 1.0 mi
- Bean Blossom GarageUnderground Storage Tanks · 1.0 mi
- UNION CITY MUNICIPAL GOVERNMENTUnderground Storage Tanks · 1.1 mi
- MR DUDLEYS RESTAURANTUnderground Storage Tanks · 1.1 mi
- Pak A Sak 15Underground Storage Tanks · 1.1 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Union City'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 Union City.
Total Sites
93
within ~10 miles of Union City
Risk Level
Elevated
Highest-severity
5 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Union City
Severity Distribution
within ~10 miles of Union City
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Union City, two things run higher than the national average within ~10 miles of Union City — Superfund (5 sites) and Toxics Release Inventory (10 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Toxics Release Inventory: TRI facilities report annual chemical releases to air, water, and land.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Check your specific parcel in Union City
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 Union City average
Your land is one point inside Union City
Everything above resolves to Union City as a whole — one PHZM band and one 28°F frost record, read across 588 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 town 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 Union City Average
Union City Average
- ●USDA Zones 6a, averaged across Union City
- ●One soil character for all of Union City
- ●Frost dates read at Union City's scale: Apr 8 to Oct 30
YOUR Parcel
- ✓Your exact zone, not Union City's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Union City
Pull a site-specific report for your exact address in Union City, Ohio — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Union City averages can't show:
We read public map data around Union City — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Union City average
How we know this about Union City
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this town’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Union City’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 town grain anywhere on this page — there is no town-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 Union City
When does frost risk typically end in Union City?
The last hard freeze (28°F) in Union City 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 Union City?
The first hard freeze (28°F) in Union City typically arrives around Oct 30, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 16, so the watching starts about Sep 30 — about 205 days after the spring freeze cleared.
How long is the growing season in Union City?
Measured between 28°F hard freezes, Union City sees about 205 frost-free days — roughly Apr 8 through Oct 30, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 29 to Oct 16, about 170 days.
Is the soil safe to grow vegetables in Union City?
The federal record around Union City is a meaningful one — 93 documented sites, mostly Underground Storage Tanks entries (51), the nearest Toxics Release Inventory record about 0.3 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 Union City?
From about Sep 30 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 30 (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 30. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Union City's scale — its 6a band and its 205-day season. Your yard writes its own version of Union City'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 Union City’s own scale
7 of the readings below were taken at Union City's own scale — its own ~205-day season between 28°F freezes, the 588 acres it covers and 93 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Union City's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Union City's own 28°F hard-freeze dates, about Apr 8 and Oct 30 and the ~205-day span between themNOAA 1991–2020 Climate Normals
- 93 documented contamination sites on the federal record near Union City, the closest Toxics Release Inventory record about 0.3 miles out from the town centreFederal environmental registers
- Union City's boundary and the 588 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~205-day seasonGrowable Ground crop-matching engine
- The ecoregion at Union City's own centroid, the Eastern Corn Belt PlainsUS EPA Level III Ecoregions
- Lanternfly survey cells around Union City checked, none carrying a detectionlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Union City's 588 acres read through its county's SSURGO summaryfrom Darke County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Darke County
- The growing challenges every Ohio grower plans around — written at state scale, so they stay on the state guidefrom Ohio
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Darke County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Union City's 588 acreswhy one lot differs from the next →
- Which side of Union City you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 588 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Toxics Release Inventory record about 0.3 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 Union City-wide figureread your own land →
More in Ohio
Wider growing context
What grows across OhioUnion City sits outside our named growing regions, so Ohio as a whole is its closest context here.
Nearby growing guides