South Williamson, Kentucky, sits in USDA hardiness zone 7a — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
Well-matched crops include cabbage, hazelnut, california poppy, and collard greens, and the gap between "grows in the area" and "grows in your yard" is closed by soil, sun, and drainage.
Even in South Williamson, 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 South Williamson 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 South Williamson — soil, climate, flood, and parcel records. How we handle your address.
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South Williamson — the short answer
South Williamson, Kentucky: USDA zone 7a, about 228 days between hard freezes, across 1K acres of town.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 26
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 9
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~228
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 1K 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 7a is South Williamson's average, not your lot's — a low corner or a tree line moves it. Against South Williamson's 228-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in South Williamson
Each reading below is measured for South Williamson itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredSouth Williamson runs about 228 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
MeasuredSouth Williamson 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 South Williamson is in
South Williamson sits in the Central Appalachians — EPA Level III, inside the wider Eastern Temperate Forests. That is read at South Williamson's own centroid rather than borrowed from Pike County.
What Grows in South Williamson
Every plant below cleared South Williamson's own zone 7a and its 228-day season. Each card opens that plant's Kentucky profile. How we score.
Is it too late to plant in South Williamson?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. 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 9 — 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 South Williamson
Survey cells within 31 miles of South Williamson checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 75 miles off. What to watch for.
What's on the federal record near South Williamson
Closest first, within ~10 miles of South Williamson. Listing isn't leaking, and distance isn't exposure.
- Branhams Citgo IncUnderground Storage Tanks · 1500 ft
- Big Hill Leasing Co PropertyUnderground Storage Tanks · 1800 ft
- Williamson Appalachian Regional Hospital (former location)Underground Storage Tanks · 2000 ft
- WILLIAMSON RESIDENTIAL MERCURY SITESuperfund · 0.5 mi
- BELL ATLANTIC/WILLIAMSON SOCUnderground Storage Tanks · 0.6 mi
- SUPERAMERICA 9292Underground Storage Tanks · 0.7 mi
- Appalachian Tobacco & GasUnderground Storage Tanks · 0.7 mi
- FIRST AVENUE PARKING LOTUnderground Storage Tanks · 0.8 mi
- CVS PHARMACY #6340Brownfields · 0.8 mi
- Fast Lane No 6Underground Storage Tanks · 0.8 mi
- APPALACHIAN POWER COMPANYUnderground Storage Tanks · 0.8 mi
- MOORE CHRYSLERUnderground Storage Tanks · 0.8 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from South Williamson'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 South Williamson.
Total Sites
297
within ~10 miles of South Williamson
Risk Level
Elevated
Highest-severity
2 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of South Williamson
Severity Distribution
within ~10 miles of South Williamson
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around South Williamson, Nitrate runs higher than the national average — 108 sites within ~10 miles of South Williamson. 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 South Williamson
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 South Williamson average
Your land is one point inside South Williamson
Everything above resolves to South Williamson as a whole — one PHZM band and one 28°F frost record, read across 1K 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 South Williamson Average
South Williamson Average
- ●USDA Zones 7a, averaged across South Williamson
- ●One soil character for all of South Williamson
- ●Frost dates read at South Williamson's scale: Mar 26 to Nov 9
YOUR Parcel
- ✓Your exact zone, not South Williamson's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in South Williamson
Pull a site-specific report for your exact address in South Williamson, Kentucky — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that South Williamson averages can't show:
We read public map data around South Williamson — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the South Williamson average
How we know this about South Williamson
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 South Williamson’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 South Williamson
When does frost risk typically end in South Williamson?
The last hard freeze (28°F) in South Williamson 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.
When is the first frost in South Williamson?
The first hard freeze (28°F) in South Williamson typically arrives around Nov 9, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 26, so the watching starts about Oct 10 — about 228 days after the spring freeze cleared.
How long is the growing season in South Williamson?
Measured between 28°F hard freezes, South Williamson sees about 228 frost-free days — roughly Mar 26 through Nov 9, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 16 to Oct 26, about 193 days.
Is the soil safe to grow vegetables in South Williamson?
The federal record around South Williamson is a meaningful one — 297 documented sites, mostly Underground Storage Tanks entries (160), the nearest Underground Storage Tanks 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 South Williamson?
From about Oct 10 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 Nov 9 (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 Nov 9. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at South Williamson's scale — its 7a band and its 228-day season. Your yard writes its own version of South Williamson'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 South Williamson’s own scale
7 of the readings below were taken at South Williamson's own scale — its own ~228-day season between 28°F freezes, the 1,263 acres it covers and 297 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- South Williamson's own USDA hardiness band, zones 7aUSDA PHZM 2023
- South Williamson's own 28°F hard-freeze dates, about Mar 26 and Nov 9 and the ~228-day span between themNOAA 1991–2020 Climate Normals
- 297 documented contamination sites on the federal record near South Williamson, the closest Underground Storage Tanks record about 0.3 miles out from the town centreFederal environmental registers
- South Williamson's boundary and the 1,263 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~228-day seasonGrowable Ground crop-matching engine
- The ecoregion at South Williamson's own centroid, the Central AppalachiansUS EPA Level III Ecoregions
- Lanternfly survey cells around South Williamson 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 South Williamson's 1,263 acres read through its county's SSURGO summaryfrom Pike County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Pike County
- The growing challenges every Kentucky grower plans around — written at state scale, so they stay on the state guidefrom Kentucky
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Pike County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among South Williamson's 1,263 acreswhy one lot differs from the next →
- Which side of South Williamson you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,263 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks 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 South Williamson-wide figureread your own land →
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