Clarion County, in 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.
Clarion County lies within Appalachia — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Clarion County holds more than one microclimate.
Soils and elevations shift across Clarion 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 Clarion County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Clarion County — the short answer
Clarion County, Pennsylvania: USDA zone 6a, about 183 days between hard freezes, across 385K acres.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 27
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 27
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~183
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 385K 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 Clarion County's average, not your lot's — a low corner or a tree line moves it. Against Clarion County's 183-day season, see what your own ground reads.
Heat in Clarion County
Across a year, Clarion County accumulates about 2,228 growing degree days above 50°F, about 319 fewer than the middle Pennsylvania county — ahead of 15 of Pennsylvania’s 67 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 Clarion County
Across Clarion County, the ground is predominantly Ultisols, where Cavode, Cookport, and Gilpin are the most extensive named soil series. The soil is generally well drained with a silt loam surface. Topsoil pH runs about 4.6–5.6, strongly acidic. Rainfall drains through hydrologic group C/D soils.
Soil order
Ultisols
Drainage
Well drained
Prime farmland
14%
Hydric soils
4%
Soil still varies lot by lot — soil types explained.
How the ground varies across Clarion County
The USDA soil survey maps 49% of Clarion County as well drained — but another 50% drains differently: 33% moderately well drained, 12% somewhat poorly drained.
Cavode is the most extensive named soil at 11% of mapped acres, then Cookport (11%) and Gilpin (10%).
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 Clarion County
Each reading below is measured for Clarion 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 Clarion County are well drained, in hydrologic group C/D — 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 Clarion County runs about pH 4.6–5.6, 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
MeasuredClarion County runs about 183 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
MeasuredClarion 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 Clarion County is in
Clarion County spans 2 EPA Level III ecoregions — Western Allegheny Plateau (84%) and North Central Appalachians (16%). 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 Clarion County
We scored all 1,086 plants against Clarion County's own USDA zone 6a and its own 183-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 Pennsylvania profile.
Is it too late to plant in Clarion County?
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 Mar 30; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 27 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 27 — long-season crops need about 90 days of runway, quick greens only 30. Even past midsummer there is room for a true fall garden here, and garlic planted near the close carries the momentum into next year.
Documented around Clarion County
Spotted lanternfly documented 2 miles from Clarion County, first recorded 2019. What to watch for.
- monarch butterfly3 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Clarion County
USGS estimates 36,877 lb of Glyphosate on Clarion County farmland in 2019, its largest by weight, ahead of Atrazine (11,474 lb) and Metolachlor & Metolachlor-s (10,891 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 Clarion County — and how to grow with it.
We checked the federal record across Clarion County — 476 documented sites across 5 of the 9 source types we track.
The most significant on record: 18 Toxics Release Inventory facilities. Active industrial facilities reporting chemical releases to air, water, and land.
There's a meaningful federal record across Clarion 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 Clarion County
Closest first, across Clarion County. Listing isn't leaking, and distance isn't exposure.
- JIFFY MINI MART 5Underground Storage Tanks · 1400 ft
- CLAIRCO ENTERPRISESUnderground Storage Tanks · 1900 ft
- FRED L BURNS WHSEUnderground Storage Tanks · 1900 ft
- TIMBERWOLF LODGEUnderground Storage Tanks · 0.5 mi
- RIVERVIEW INTERMEDIATE UNITUnderground Storage Tanks · 0.5 mi
- BENNYS CEMENT SVCUnderground Storage Tanks · 0.6 mi
- BECKWITH MACHUnderground Storage Tanks · 0.6 mi
- ASTRO MFGUnderground Storage Tanks · 0.6 mi
- CLARION COUNTY PARKBrownfields · 0.9 mi
- PINEY POWER PLTBrownfields · 1.0 mi
- CLARION HOSPUnderground Storage Tanks · 1.3 mi
- PINEY CREEK LPToxics Release Inventory · 1.4 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Clarion 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 Clarion County.
Total Sites
476
across Clarion County
Risk Level
Elevated
Highest-severity
18 Toxics Release Inventory facilities
Sources Checked
across Clarion County
Severity Distribution
across Clarion County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Clarion County, Nitrate runs higher than the national average — 208 sites across Clarion County. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
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 Clarion 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 Clarion County average
Your land is one point inside Clarion County
Everything above resolves to Clarion County as a whole — one PHZM band and one county frost record, read across 385K 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 Clarion County Average
Clarion County Average
- ●USDA Zones 6a, averaged across Clarion County
- ●One soil character for all of Clarion County
- ●Frost dates read at Clarion County's scale: Apr 27 to Oct 27
YOUR Parcel
- ✓Your exact zone, not Clarion County's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Clarion County
Pull a site-specific report for your exact address in Clarion County, Pennsylvania — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Clarion County averages can't show:
We read public map data around Clarion County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Clarion County average
How we know this about Clarion 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 Clarion County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Clarion County
When does frost risk typically end in Clarion County?
The last hard freeze (28°F) in Clarion County typically lands around Apr 27, 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 18.
How long is the growing season in Clarion County?
Measured between 28°F hard freezes, Clarion County sees about 183 frost-free days — roughly Apr 27 through Oct 27, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 18 to Oct 13, about 148 days.
Is the soil safe to grow vegetables in Clarion County?
The federal record around Clarion County is a meaningful one — 476 documented sites, mostly Nitrate entries (208), 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.
Everything above is measured at Clarion County's scale — its 6a band and its 183-day season. Your yard writes its own version of Clarion 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 Pennsylvania's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Clarion County’s own scale
9 of the readings below were taken at Clarion County's own scale — its own ~183-day span between 28°F freezes, the 3 most extensive soil series mapped here and 476 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Clarion County's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Clarion County's own 28°F hard-freeze dates and its ~183-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Clarion CountyUSDA NRCS SSURGO
- 476 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Underground Storage Tanks record about 0.3 miles outFederal environmental registers
- Clarion County's boundary and the 384,534 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~183-day seasonGrowable Ground crop-matching engine
- The 2 ecoregions Clarion County spans, Western Allegheny Plateau the largestUS EPA Level III Ecoregions
- Open occurrence records documented in Clarion County for a tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Clarion County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every Pennsylvania grower plans around — written at state scale, so they stay on the state guidefrom Pennsylvania
What this page can’t tell you
- How the season shifts across Clarion County — the ~183 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 Clarion County's 384,534 acreswhy one lot differs from the next →
- Which of those 476 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 Clarion Countyread your own land →