Allen County, in Kentucky, sits in USDA hardiness zone 7a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
Crops well matched to these conditions include cabbage, hazelnut, california poppy, and collard greens — though what thrives on any one site still turns on its specific soil, sun, and drainage.
Allen County lies within the Pennyroyal / Pennyrile (South-Central Kentucky Karst Plateau) — a regional growing area with its own character.
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, Kentucky: USDA zone 7a, about 229 days between hard freezes, across 220K acres.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 26
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Nov 10
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~229
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 220K 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 7a is Allen County's average, not your lot's — a low corner or a tree line moves it. Against Allen County's 229-day season, see what your own ground reads.
Heat and winter chill in Allen County
Across a year, Allen County accumulates about 4,093 growing degree days above 50°F, about 433 more than the middle Kentucky county — ahead of 96 of Kentucky’s 120 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.
Winter banks about 2,273 hours below 45°F. Chill is what tells a fruit tree its dormancy is over, and it is set by climate rather than by anything you can build.
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 Christian, Bedford, and Mountview are the most extensive named soil series. The soil is generally well drained with a gravelly silt loam surface. Topsoil pH runs about 4.8–5.5, strongly acidic. Rainfall drains through hydrologic group B soils.
Soil order
Alfisols
Drainage
Well drained
Prime farmland
27%
Hydric soils
0%
Soil still varies lot by lot — soil types explained.
How the ground varies across Allen County
The USDA soil survey maps 87% of Allen County as well drained — but another 12% drains differently: 10% moderately well drained, 1% somewhat poorly drained.
Christian is the most extensive named soil at 25% of mapped acres, then Bedford (10%) and Mountview (9%).
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 well drained, in hydrologic group B — ground that drains quickly.
The upside is soil you can work early in spring and roots that never drown; the cost is that fast-draining ground dries out fast and leaches nutrients away before plants can use them.
Work in compost and mulch to hold moisture and feed, and water more often in short doses than deep and rarely.
USDA NRCS SSURGO
Surface pH
MeasuredTopsoil across Allen County runs about pH 4.8–5.5, on the acidic side.
Blueberries, potatoes, and rhododendrons thrive in it, but most vegetables start locking out nutrients below about pH 6.0 and grow pale and stunted no matter how much you feed them.
A measured lime application raises pH for the crops that need it — but test first, because the right rate depends on your own soil, not the county average.
USDA NRCS SSURGO
Season length
MeasuredAllen County runs about 229 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 7a.
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 sits in the Interior Plateau — EPA Level III, inside the wider Eastern Temperate Forests. One consistent ecological setting across the whole county.
What Grows in Allen County
We scored all 1,086 plants against Allen County's own USDA zone 7a and its own 229-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 Kentucky 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 Feb 26; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 26 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 10 — 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.
What gets applied to farmland in Allen County
USGS estimates 22,106 lb of Glyphosate on Allen County farmland in 2019, its largest by weight, ahead of 2,4-d (21,789 lb) and Atrazine (6,287 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 — 174 documented sites across 5 of the 9 source types we track.
The most significant on record: 5 Toxics Release Inventory facilities. Active industrial facilities reporting chemical releases to air, water, and land.
The federal record across Allen County is a modest one — a typical footprint for a growing area. Nothing here calls for alarm; it's worth knowing which recorded sites sit closest to where you grow, and each one on the map carries its type and location. If one turns out to be a near neighbor, a one-time soil test settles the question.
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.
- Larry Stovall PropertyUnderground Storage Tanks · 450 ft
- MAPCO Express #1070Underground Storage Tanks · 500 ft
- Lamberth Farm & GardenUnderground Storage Tanks · 650 ft
- Harrison & GoinUnderground Storage Tanks · 1000 ft
- House Of StyleUnderground Storage Tanks · 1000 ft
- Marjorie J Eldred BldgUnderground Storage Tanks · 1100 ft
- Ashland MartUnderground Storage Tanks · 1100 ft
- New Roe GroUnderground Storage Tanks · 1200 ft
- Hobby Dye & Reed BldgUnderground Storage Tanks · 1300 ft
- North Central TelephoneUnderground Storage Tanks · 1300 ft
- Minit Mart #518Underground Storage Tanks · 1300 ft
- Marvin Wood LumberUnderground Storage Tanks · 1300 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
174
across Allen County
Risk Level
Moderate
Highest-severity
5 Toxics Release Inventory facilities
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, Nitrate runs higher than the national average — 84 sites across Allen County. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
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 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 220K 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 7a, averaged across Allen County
- ●One soil character for all of Allen County
- ●Frost dates read at Allen County's scale: Mar 26 to Nov 10
YOUR Parcel
- ✓Your exact zone, not Allen County's 7a
- ✓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, Kentucky — 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 Mar 26, 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 16.
How long is the growing season in Allen County?
Measured between 28°F hard freezes, Allen County sees about 229 frost-free days — roughly Mar 26 through Nov 10, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 16 to Oct 27, about 194 days.
Is the soil safe to grow vegetables in Allen County?
The federal record around Allen County shows 174 documented sites, mostly Nitrate entries (84), 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.
Everything above is measured at Allen County's scale — its 7a band and its 229-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 Kentucky's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Allen County’s own scale
8 of the readings below were taken at Allen County's own scale — its own ~229-day span between 28°F freezes, the 3 most extensive soil series mapped here and 174 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 7aUSDA PHZM 2023
- Allen County's own 28°F hard-freeze dates and its ~229-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
- 174 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Underground Storage Tanks record under a tenth of a mile outFederal environmental registers
- Allen County's boundary and the 219,983 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~229-day seasonGrowable Ground crop-matching engine
- Allen County sitting wholly inside the Interior PlateauUS EPA Level III Ecoregions
- 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 Kentucky grower plans around — written at state scale, so they stay on the state guidefrom Kentucky
What this page can’t tell you
- How the season shifts across Allen County — the ~229 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 219,983 acreswhy one lot differs from the next →
- Which of those 174 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 →