Simpson County, in Kentucky, sits in USDA hardiness zone 7a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
On paper, cabbage, hazelnut, california poppy, and collard greens all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Simpson 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
Simpson County holds more than one microclimate.
Soils and elevations shift across Simpson 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 Simpson County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Simpson County — the short answer
Simpson County, Kentucky: USDA zone 7a, about 230 days between hard freezes, across 150K acres.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 25
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Nov 10
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~230
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 150K 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 Simpson County's average, not your lot's — a low corner or a tree line moves it. Against Simpson County's 230-day season, see what your own ground reads.
Heat and winter chill in Simpson County
Across a year, Simpson County accumulates about 4,090 growing degree days above 50°F, about 430 more than the middle Kentucky county — ahead of 95 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 2,346 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 Simpson County
Across Simpson County, the ground is predominantly Alfisols, where Mountview, Baxter, and Nicholson are the most extensive named soil series. The soil is generally well drained with a silt loam surface. Topsoil pH runs about 5.0–5.9, strongly acidic. Rainfall drains through hydrologic group B soils.
Soil order
Alfisols
Drainage
Well drained
Prime farmland
53%
Hydric soils
3%
Soil still varies lot by lot — soil types explained.
How the ground varies across Simpson County
The USDA soil survey maps 88% of Simpson County as well drained — but another 12% drains differently: 6% moderately well drained, 3% somewhat poorly drained.
Mountview is the most extensive named soil at 27% of mapped acres, then Baxter (27%) and Nicholson (6%).
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 Simpson County
Each reading below is measured for Simpson 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 Simpson 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 Simpson County runs about pH 5.0–5.9, 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
MeasuredSimpson County runs about 230 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
MeasuredSimpson 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 Simpson County is in
Simpson 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 Simpson County
We scored all 1,086 plants against Simpson County's own USDA zone 7a and its own 230-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 Simpson County?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Feb 25; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 25 (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. There is slack in a calendar like this — late plantings, second rounds of favorites, and a fall bench that keeps beds working.
Documented around Simpson County
- monarch butterfly1 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Simpson County
USGS estimates 160,194 lb of Glyphosate on Simpson County farmland in 2019, its largest by weight, ahead of Metolachlor & Metolachlor-s (71,954 lb) and Atrazine (69,986 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 Simpson County — and how to grow with it.
We checked the federal record across Simpson County — 161 documented sites across 5 of the 9 source types we track.
The most significant on record: 1 Superfund site (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 Simpson 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 Simpson County
Closest first, across Simpson County. Listing isn't leaking, and distance isn't exposure.
- AIRCO INDUSTRIAL GASESToxics Release Inventory · 350 ft
- Savings StationUnderground Storage Tanks · 850 ft
- Holiday Gulf/Bp (Service)Underground Storage Tanks · 900 ft
- Lane King Chevrolet PontiacUnderground Storage Tanks · 1000 ft
- Chevron Service StationUnderground Storage Tanks · 1200 ft
- MERITOR HEAVY BRAKING SYSTEMS USA INCToxics Release Inventory · 1400 ft
- MERITOR HEAVY BRAKING SYSTEMS USA INCBrownfields · 1400 ft
- Minit Mart 57Underground Storage Tanks · 2200 ft
- Suburban FurnitureUnderground Storage Tanks · 2200 ft
- Bennett Tire ServiceUnderground Storage Tanks · 0.6 mi
- Ronnie Blacks Auto SalesUnderground Storage Tanks · 0.7 mi
- DRACKETT INCToxics Release Inventory · 0.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Simpson 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 Simpson County.
Total Sites
161
across Simpson County
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
across Simpson County
Severity Distribution
across Simpson County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Simpson County, two things run higher than the national average across Simpson County — Toxics Release Inventory (20 sites) and Underground Storage Tanks (106 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.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Simpson 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 Simpson County average
Your land is one point inside Simpson County
Everything above resolves to Simpson County as a whole — one PHZM band and one county frost record, read across 150K 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 Simpson County Average
Simpson County Average
- ●USDA Zones 7a, averaged across Simpson County
- ●One soil character for all of Simpson County
- ●Frost dates read at Simpson County's scale: Mar 25 to Nov 10
YOUR Parcel
- ✓Your exact zone, not Simpson County's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Simpson County
Pull a site-specific report for your exact address in Simpson County, Kentucky — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Simpson County averages can't show:
We read public map data around Simpson County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Simpson County average
How we know this about Simpson 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 Simpson County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Simpson County
When does frost risk typically end in Simpson County?
The last hard freeze (28°F) in Simpson County typically lands around Mar 25, 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 15.
How long is the growing season in Simpson County?
Measured between 28°F hard freezes, Simpson County sees about 230 frost-free days — roughly Mar 25 through Nov 10, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 15 to Oct 27, about 195 days.
Is the soil safe to grow vegetables in Simpson County?
The federal record around Simpson County is a meaningful one — 161 documented sites, mostly Underground Storage Tanks entries (106), the nearest Toxics Release Inventory record under a tenth of a mile 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 Simpson County's scale — its 7a band and its 230-day season. Your yard writes its own version of Simpson 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 Simpson County’s own scale
9 of the readings below were taken at Simpson County's own scale — its own ~230-day span between 28°F freezes, the 3 most extensive soil series mapped here and 161 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Simpson County's own USDA hardiness band, zones 7aUSDA PHZM 2023
- Simpson County's own 28°F hard-freeze dates and its ~230-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Simpson CountyUSDA NRCS SSURGO
- 161 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Toxics Release Inventory record under a tenth of a mile outFederal environmental registers
- Simpson County's boundary and the 149,878 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~230-day seasonGrowable Ground crop-matching engine
- Simpson County sitting wholly inside the Interior PlateauUS EPA Level III Ecoregions
- Open occurrence records documented in Simpson County for a tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Simpson 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 Simpson County — the ~230 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 Simpson County's 149,878 acreswhy one lot differs from the next →
- Which of those 161 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 Simpson Countyread your own land →