Karns City, Pennsylvania, sits in USDA hardiness zone 6a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Expect cabbage, hazelnut, lavender, and collard greens to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
Even in Karns City, 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 Karns City 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 Karns City — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Karns City — the short answer
Karns City, Pennsylvania: USDA zone 6a, about 189 days between hard freezes, across 232 acres of town.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 23
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 29
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~189
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 232 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 6a is Karns City's average, not your lot's — a low corner or a tree line moves it. Against Karns City's 189-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Karns City
Each reading below is measured for Karns City itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredKarns City runs about 189 days between hard freezes — a moderate growing season.
There is room for the full run of cool-season crops plus a warm-season main crop, but the calendar is tight enough that a late spring or early fall frost still decides how much finishes.
Time warm-season transplants to your last hard freeze, and a few weeks of season extension turns a near-miss harvest into a sure one.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredKarns City 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 Karns City is in
Karns City sits in the Western Allegheny Plateau — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Karns City's own centroid rather than borrowed from Butler County.
What Grows in Karns City
Every plant below cleared Karns City's own zone 6a and its 189-day season. Each card opens that plant's Pennsylvania profile. How we score.
Is it too late to plant in Karns City?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Mar 26; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 23 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 29 — long-season crops need about 90 days of runway, quick greens only 30. As the window narrows, the plantings just get faster — fall brassicas, then greens, then garlic to finish.
Documented around Karns City
Spotted lanternfly documented 2 miles from Karns City, first recorded 2022. What to watch for.
What's on the federal record near Karns City
Closest first, within ~10 miles of Karns City. Listing isn't leaking, and distance isn't exposure.
- CALUMET KARNS CITY REFININGToxics Release Inventory · 700 ft
- CALUMET KARNS CITY REFININGBrownfields · 700 ft
- CALUMET KARNS CITY REF LLCUnderground Storage Tanks · 800 ft
- ROTTMANS SVC STAUnderground Storage Tanks · 1300 ft
- HOBAUGH AUTO PARTSUnderground Storage Tanks · 2000 ft
- FAIRVIEW TWP BLDGUnderground Storage Tanks · 2500 ft
- TOTAL CLEAN LLCBrownfields · 0.6 mi
- KARNS CITY HIGH SCHBrownfields · 0.6 mi
- SONNEBORN, LLC.Toxics Release Inventory · 1.2 mi
- SONNEBORN, LLC.Brownfields · 1.2 mi
- PA DOT RTE 268 PETROLIA BRIDGE PROJUnderground Storage Tanks · 1.4 mi
- MILLERSUnderground Storage Tanks · 1.4 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Karns City'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 Karns City.
Sources Checked
within ~10 miles of Karns City
Severity Distribution
within ~10 miles of Karns City
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Karns City, two things run higher than the national average within ~10 miles of Karns City — Toxics Release Inventory (11 sites) and Underground Storage Tanks (68 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.
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 Karns City
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 Karns City average
Your land is one point inside Karns City
Everything above resolves to Karns City as a whole — one PHZM band and one 28°F frost record, read across 232 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 Karns City Average
Karns City Average
- ●USDA Zones 6a, averaged across Karns City
- ●One soil character for all of Karns City
- ●Frost dates read at Karns City's scale: Apr 23 to Oct 29
YOUR Parcel
- ✓Your exact zone, not Karns City's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Karns City
Pull a site-specific report for your exact address in Karns City, Pennsylvania — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Karns City averages can't show:
We read public map data around Karns City — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Karns City average
How we know this about Karns City
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 Karns City’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 Karns City
When does frost risk typically end in Karns City?
The last hard freeze (28°F) in Karns City typically lands around Apr 23, 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 May 14.
When is the first frost in Karns City?
The first hard freeze (28°F) in Karns City typically arrives around Oct 29, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 15, so the watching starts about Sep 29 — about 189 days after the spring freeze cleared.
How long is the growing season in Karns City?
Measured between 28°F hard freezes, Karns City sees about 189 frost-free days — roughly Apr 23 through Oct 29, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 14 to Oct 15, about 154 days.
Is the soil safe to grow vegetables in Karns City?
The federal record around Karns City is a meaningful one — 110 documented sites, mostly Underground Storage Tanks entries (68), the nearest Toxics Release Inventory 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.
How do I protect my plants from frost in Karns City?
From about Sep 29 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 Oct 29 (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 Oct 29. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Karns City's scale — its 6a band and its 189-day season. Your yard writes its own version of Karns City'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 Karns City’s own scale
7 of the readings below were taken at Karns City's own scale — its own ~189-day season between 28°F freezes, the 232 acres it covers and 110 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Karns City's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Karns City's own 28°F hard-freeze dates, about Apr 23 and Oct 29 and the ~189-day span between themNOAA 1991–2020 Climate Normals
- 110 documented contamination sites on the federal record near Karns City, the closest Toxics Release Inventory record about 0.1 miles out from the town centreFederal environmental registers
- Karns City's boundary and the 232 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~189-day seasonGrowable Ground crop-matching engine
- The ecoregion at Karns City's own centroid, the Western Allegheny PlateauUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Karns Citylydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Karns City's 232 acres read through its county's SSURGO summaryfrom Butler County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Butler County
- The growing challenges every Pennsylvania grower plans around — written at state scale, so they stay on the state guidefrom Pennsylvania
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Butler County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Karns City's 232 acreswhy one lot differs from the next →
- Which side of Karns City you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 232 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Toxics Release Inventory record about 0.1 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 Karns City-wide figureread your own land →
More in Pennsylvania
Growing region
Nearby growing guides