Darke County, in Ohio, sits in USDA hardiness zone 6a — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
These conditions suit cabbage, hazelnut, lavender, and collard greens — a starting list any specific site will trim or extend with its own soil, sun, and drainage.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Darke County holds more than one microclimate.
Soils and elevations shift across Darke County, so your frost dates and drainage aren't the county average. 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 Darke County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Darke County — the short answer
Darke County, Ohio: USDA zone 6a, about 202 days between hard freezes, across 383K acres.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 9
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 28
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~202
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 383K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are county 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 Darke County's average, not your lot's — a low corner or a tree line moves it. Against Darke County's 202-day season, see what your own ground reads.
Heat in Darke County
Across a year, Darke County accumulates about 2,906 growing degree days above 50°F, about 16 fewer than the middle Ohio county — ahead of 38 of Ohio’s 88 counties. Degree days are the heat a crop actually gets to work with — more of them is more room to ripen a long-season crop before the freeze closes the window.
Grounded in PRISM Climate Group, Oregon State University — 1991–2020 monthly normals
Soil in Darke County
Across Darke County, the ground is predominantly Alfisols, where Crosby, Blount, and Miamian are the most extensive named soil series. The soil is generally somewhat poorly drained with a silt loam surface. Topsoil pH runs about 6.2–6.5, slightly acidic. Rainfall drains through hydrologic group C/D soils.
Soil order
Alfisols
Drainage
Somewhat poorly drained
Prime farmland
21%
Hydric soils
27%
Soil still varies lot by lot — soil types explained.
How the ground varies across Darke County
The USDA soil survey maps 45% of Darke County as somewhat poorly drained — but another 55% drains differently: 18% poorly drained, 17% well drained.
Crosby is the most extensive named soil at 26% of mapped acres, then Blount (18%) and Miamian (14%).
Which of them your own lot sits on is a parcel question, not a county one. Check your address for the survey at your boundary.
What this means for growing in Darke County
Each reading below is measured for Darke County itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Drainage
MeasuredThe dominant soils across Darke County are somewhat poorly drained, in hydrologic group C/D — ground that sheds water slowly.
Beds can stay saturated for days after heavy rain, and the roots of most vegetables, berries, and fruit trees suffocate or rot in soil that never drains.
Raised beds or mounded rows lift roots above the wet zone; choose water-tolerant crops for the lowest spots.
USDA NRCS SSURGO
Surface pH
MeasuredTopsoil across Darke County runs about pH 6.2–6.5, close to neutral.
This is the range most vegetables prefer — one correction you probably do not have to make, which is genuinely good news for a new bed.
Keep it there with compost rather than lime or sulfur, and only amend if your own soil test says otherwise.
USDA NRCS SSURGO
Season length
MeasuredDarke County runs about 202 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
MeasuredDarke County 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 Darke County is in
Darke County sits in the Eastern Corn Belt Plains — EPA Level III, inside the wider Eastern Temperate Forests. One consistent ecological setting across the whole county.
What Grows in Darke County
We scored all 1,086 plants against Darke County's own USDA zone 6a and its own 202-day season between hard freezes, using the same matching engine that runs a full parcel report. These cleared both. Sun, soil pH and drainage vary lot by lot — those are the parcel questions below. Each card opens that plant's Ohio profile.
Is it too late to plant in Darke County?
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 12; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 9 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 28 — long-season crops need about 90 days of runway, quick greens only 30. There is slack in a calendar like this — late plantings, second rounds of favorites, and a fall bench that keeps beds working.
Documented around Darke County
Survey cells within 31 miles of Darke County checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 42 miles off. What to watch for.
- monarch butterfly12 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Darke County
USGS estimates 200,290 lb of Glyphosate on Darke County farmland in 2019, its largest by weight, ahead of Acetochlor (92,827 lb) and Atrazine (89,440 lb).
Farmland across the whole county, not any one lot. Check your address for the site-by-site record.
Safe to Grow Here?
What the federal record shows across Darke County — and how to grow with it.
We checked the federal record across Darke County — 229 documented sites across 6 of the 9 source types we track.
The most significant on record: 4 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
There's a meaningful federal record across Darke County — worth a look before you plant food, not a reason to hold back from growing. Proximity to a documented site is information, not a diagnosis of any one yard. A soil test before new food beds is the sensible precaution here, and the map shows exactly which sites sit where, so you can see what's actually near you.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Darke County
Closest first, across Darke County. Listing isn't leaking, and distance isn't exposure.
- LOWES #2524Brownfields · 1000 ft
- GREENVILLE PARTY MART (SHELL)Underground Storage Tanks · 1600 ft
- WAL-MART NO 2035Brownfields · 1800 ft
- KROGER FUEL CENTER #833Underground Storage Tanks · 1900 ft
- KROGER #833Brownfields · 1900 ft
- DAVE KNAPP FORDBrownfields · 2300 ft
- EXPRESS BEER & WINE DRIVE THRUUnderground Storage Tanks · 2400 ft
- WHIRLPOOL - GREENVILLEBrownfields · 2400 ft
- WHIRLPOOL - GREENVILLEToxics Release Inventory · 2400 ft
- J TEC INCBrownfields · 2400 ft
- BRUMBAUGH CONSTRUCTION, INC.Underground Storage Tanks · 2500 ft
- TRACTOR SUPPLY COMPANY #671Brownfields · 2500 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Darke County'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 Darke County.
Sources Checked
across Darke County
Severity Distribution
across Darke County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Darke County, two things run higher than the national average across Darke County — Toxics Release Inventory (21 sites) and Superfund (4 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Toxics Release Inventory: TRI facilities report annual chemical releases to air, water, and land.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check your specific parcel in Darke County
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 Darke County average
Your land is one point inside Darke County
Everything above resolves to Darke County as a whole — one PHZM band and one county frost record, read across 383K 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 county 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 county average.
Your Lot vs the Darke County Average
Darke County Average
- ●USDA Zones 6a, averaged across Darke County
- ●One soil character for all of Darke County
- ●Frost dates read at Darke County's scale: Apr 9 to Oct 28
YOUR Parcel
- ✓Your exact zone, not Darke County's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Darke County
Pull a site-specific report for your exact address in Darke County, Ohio — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Darke County averages can't show:
We read public map data around Darke County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Darke County average
How we know this about Darke County
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at county grain; hard-freeze dates from NOAA 1991–2020 28°F normals at this county’s own record where one resolves, and the labelled statewide window where none does; soils from the USDA NRCS SSURGO survey, area-weighted across the county’s own map units; boundaries and acreage from US Census TIGER/Line 2025; the contamination and pesticide records from the federal sources named in their beats above. Where Darke County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Darke County
When does frost risk typically end in Darke County?
The last hard freeze (28°F) in Darke County typically lands around Apr 9, 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 30.
How long is the growing season in Darke County?
Measured between 28°F hard freezes, Darke County sees about 202 frost-free days — roughly Apr 9 through Oct 28, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 30 to Oct 14, about 167 days.
Is the soil safe to grow vegetables in Darke County?
The federal record around Darke County is a meaningful one — 229 documented sites, mostly Underground Storage Tanks entries (131), the nearest Brownfields record about 0.2 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.
Everything above is measured at Darke County's scale — its 6a band and its 202-day season. Your yard writes its own version of Darke County's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
Will It Grow Here?
Zone fit is the first question — each answer below reads Ohio's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Darke County’s own scale
9 of the readings below were taken at Darke County's own scale — its own ~202-day span between 28°F freezes, the 3 most extensive soil series mapped here and 229 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Darke County's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Darke County's own 28°F hard-freeze dates and its ~202-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Darke CountyUSDA NRCS SSURGO
- 229 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Brownfields record about 0.2 miles outFederal environmental registers
- Darke County's boundary and the 382,785 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~202-day seasonGrowable Ground crop-matching engine
- Darke County sitting wholly inside the Eastern Corn Belt PlainsUS EPA Level III Ecoregions
- Open occurrence records documented in Darke County for a tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Darke County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every Ohio grower plans around — written at state scale, so they stay on the state guidefrom Ohio
What this page can’t tell you
- How the season shifts across Darke County — the ~202 days above is one reading at its centre; the 12 towns below each carry their owntowns in this county →
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Darke County's 382,785 acreswhy one lot differs from the next →
- Which of those 229 documented sites actually reaches your soil — that needs your address, the wind, and the groundwater directionhow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — none of it survives being averaged over Darke Countyread your own land →