Allen County, in Ohio, sits in USDA hardiness zone 6a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
Crops well matched to these conditions include cabbage, hazelnut, lavender, and collard greens — though what thrives on any one site still turns on its specific soil, sun, and drainage.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Allen County holds more than one microclimate.
Soils and elevations shift across Allen 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 Allen County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Allen County — the short answer
Allen County, Ohio: USDA zone 6a, about 213 days between hard freezes, across 258K acres.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 8
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Nov 7
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~213
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 258K 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 Allen County's average, not your lot's — a low corner or a tree line moves it. Against Allen County's 213-day season, see what your own ground reads.
Heat in Allen County
Across a year, Allen County accumulates about 2,960 growing degree days above 50°F, about 38 more than the middle Ohio county — ahead of 52 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 Allen County
Across Allen County, the ground is predominantly Alfisols, where Blount, Pewamo, and Glynwood are the most extensive named soil series. The soil is generally somewhat poorly drained with a silt loam surface. Topsoil pH runs about 6.4, slightly acidic. Rainfall drains through hydrologic group D soils.
Soil order
Alfisols
Drainage
Somewhat poorly drained
Prime farmland
15%
Hydric soils
35%
Soil still varies lot by lot — soil types explained.
How the ground varies across Allen County
The USDA soil survey maps 43% of Allen County as somewhat poorly drained — but another 54% drains differently: 34% very poorly drained, 17% moderately well drained.
Blount is the most extensive named soil at 42% of mapped acres, then Pewamo (26%) and Glynwood (11%).
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 Allen County
Each reading below is measured for Allen 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 Allen County are somewhat poorly drained, in hydrologic group 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 Allen County runs about pH 6.4, 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
MeasuredAllen County runs about 213 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
MeasuredAllen 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 Allen County is in
Allen County spans 2 EPA Level III ecoregions — Eastern Corn Belt Plains (93%) and Huron/Erie Lake Plains (7%). Which one your land falls in changes what grows wild there and how the ground behaves, and a county-wide answer cannot tell you which.
What Grows in Allen County
We scored all 1,086 plants against Allen County's own USDA zone 6a and its own 213-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 Allen 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 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 Nov 7 — long-season crops need about 90 days of runway, quick greens only 30. With a season this long, “too late” mostly means “switch crops” — second sowings and a full fall garden are the norm, with garlic closing the year.
Documented around Allen County
Survey cells within 31 miles of Allen County checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 58 miles off. What to watch for.
- Japanese beetle1 documented records
- monarch butterfly171 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Allen County
USGS estimates 174,343 lb of Glyphosate on Allen County farmland in 2019, its largest by weight, ahead of Atrazine (67,522 lb) and Metolachlor & Metolachlor-s (50,727 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 Allen County — and how to grow with it.
We checked the federal record across Allen County — 605 documented sites across 6 of the 9 source types we track.
The most significant on record: 9 Superfund sites (none NPL-listed). 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 Allen 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 Allen County
Closest first, across Allen County. Listing isn't leaking, and distance isn't exposure.
- OAKWOOD CORRECTIONAL FACILITYBrownfields · 750 ft
- ODOT OLD DISTRICT 1 HEADQUARTERSUnderground Storage Tanks · 850 ft
- BP OIL COBrownfields · 850 ft
- BP OIL CO. #07472Underground Storage Tanks · 900 ft
- ODOT ALLEN COUNTY GARAGEUnderground Storage Tanks · 950 ft
- CIRCLE K #5652Brownfields · 1000 ft
- Circle K 5652Underground Storage Tanks · 1100 ft
- ODOT OLD DIST 1 GARAGEUnderground Storage Tanks · 1100 ft
- MARATHON ELECTRIC MANUFACTURING CORPToxics Release Inventory · 1200 ft
- CHARLIE'S AUTO REPAIRBrownfields · 1600 ft
- STARVIN MARVIN 3548Brownfields · 1700 ft
- SPEEDWAY #3548Underground Storage Tanks · 1700 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Allen 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 Allen County.
Total Sites
605
across Allen County
Risk Level
Elevated
Highest-severity
9 Superfund sites (none NPL-listed)
Sources Checked
across Allen County
Severity Distribution
across Allen County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Allen County, two things run higher than the national average across Allen County — Toxics Release Inventory (61 sites) and Superfund (9 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
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 Allen 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 Allen County average
Your land is one point inside Allen County
Everything above resolves to Allen County as a whole — one PHZM band and one county frost record, read across 258K 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 Allen County Average
Allen County Average
- ●USDA Zones 6a, averaged across Allen County
- ●One soil character for all of Allen County
- ●Frost dates read at Allen County's scale: Apr 8 to Nov 7
YOUR Parcel
- ✓Your exact zone, not Allen County's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Allen County
Pull a site-specific report for your exact address in Allen County, Ohio — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Allen County averages can't show:
We read public map data around Allen County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Allen County average
How we know this about Allen 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 Allen County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Allen County
When does frost risk typically end in Allen County?
The last hard freeze (28°F) in Allen County 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.
How long is the growing season in Allen County?
Measured between 28°F hard freezes, Allen County sees about 213 frost-free days — roughly Apr 8 through Nov 7, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 29 to Oct 24, about 178 days.
Is the soil safe to grow vegetables in Allen County?
The federal record around Allen County is a meaningful one — 605 documented sites, mostly Underground Storage Tanks entries (278), the nearest Brownfields 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.
Everything above is measured at Allen County's scale — its 6a band and its 213-day season. Your yard writes its own version of Allen 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 Allen County’s own scale
9 of the readings below were taken at Allen County's own scale — its own ~213-day span between 28°F freezes, the 3 most extensive soil series mapped here and 605 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Allen County's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Allen County's own 28°F hard-freeze dates and its ~213-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Allen CountyUSDA NRCS SSURGO
- 605 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Brownfields record about 0.1 miles outFederal environmental registers
- Allen County's boundary and the 257,629 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~213-day seasonGrowable Ground crop-matching engine
- The 2 ecoregions Allen County spans, Eastern Corn Belt Plains the largestUS EPA Level III Ecoregions
- Open occurrence records documented in Allen County for 2 tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Allen 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 Allen County — the ~213 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 Allen County's 257,629 acreswhy one lot differs from the next →
- Which of those 605 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 Allen Countyread your own land →