Sullivan County, in Pennsylvania, sits in USDA hardiness zone 6a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Reliable performers under these conditions include apple, tomato, grape, and mountain laurel; what your own ground favors still comes down to its soil, sun, and drainage.
Sullivan 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
Sullivan County holds more than one microclimate.
Soils and elevations shift across Sullivan County, so your frost dates and drainage aren't the county average. Enter your address and we'll score 1,112 plants against your land's actual soil, sun, and frost.
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
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Quick Facts
USDA Zones
6a
Last Hard Freeze (28°F)
Apr 13
County normal — light frosts run a few weeks later
First Hard Freeze (28°F)
Nov 9
County normal — light frosts arrive a few weeks earlier
County Area
288K acres
Hardiness Zone Range
Zone maps are averages across Sullivan County. Your yard's slope, trees, and frost pockets shift what actually grows — see your land's exact reading.
Soil in Sullivan County
Across Sullivan County, the ground is predominantly Inceptisols, where Wellsboro, Oquaga, and Morris are the most extensive named soil series. The soil is generally well drained with a channery silt loam surface. Topsoil pH runs about 5.4–5.5, strongly acidic. Rainfall drains through hydrologic group D soils.
Soil order
Inceptisols
Drainage
Well drained
Prime farmland
5%
Hydric soils
6%
Soil still varies lot by lot — soil types explained.
What Grows in Sullivan County
Plants matched to Sullivan County's USDA zones 6a — each links to its full growing profile.
Is it too late to plant in Sullivan 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 16; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 13 (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. Here the season winds down slowly: late sowings, a real autumn harvest, and garlic in the ground before the first hard freeze.
Growing Challenges in Pennsylvania
What an experienced grower plans around here — each one has a move.
Rocky shale soils in the ridge-and-valley region
Build up over shale rather than into it — raised beds with imported soil give roots depth the ridge won't.
Short mountain seasons in the Poconos and Alleghenies
Mountain growers stretch the season with cold frames and fast varieties — the missing weeks are recoverable.
Deer pressure is among the highest in the US
In the hardest-hit deer country, a tall fence is the only reliable line — resistant plants cover the rest.
For cultivar selection, pest pressure, and planting-time guidance specific to Pennsylvania, the Penn State Extension is the authoritative local source.
Safe to Grow Here?
What the federal record shows across Sullivan County — and how to grow with it.
We checked the federal record across Sullivan County — 123 documented sites across 5 of the 9 source types we track.
The most significant on record: 1 Toxics Release Inventory facility. Active industrial facilities reporting chemical releases to air, water, and land.
The federal record across Sullivan 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.
Environmental Intelligence
Understanding what's nearby helps you make informed decisions about where and how to grow.
Total Sites
123
across Sullivan County
Risk Level
Moderate
Highest-severity
1 Toxics Release Inventory facility
Sources Checked
across Sullivan County
Severity Distribution
across Sullivan County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Sullivan County, Nitrate runs higher than the national average — 58 sites nearby. 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 Sullivan County
Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,112 plant recommendations.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources analyzed in seconds
Your Specific Parcel Matters
Sullivan County Average
- ●USDA Zones 6a
- ●Generic soil type for the area
- ●State-average frost dates
YOUR Parcel
- ✓Your exact hardiness zone
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Sullivan County
Pull a site-specific report for your exact address in Sullivan County, Pennsylvania — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources analyzed in seconds
Key Growing Facts for Sullivan County, Pennsylvania
- USDA Hardiness Zones: 6a (USDA PHZM 2023)
- Last Hard Freeze (28°F): Apr 13 (county normal, NOAA 1991–2020 Climate Normals — light frosts can follow for a few weeks)
- First Hard Freeze (28°F): Nov 9 (county normal, NOAA 1991–2020 Climate Normals — light frosts can arrive a few weeks earlier)
- Days Between Hard Freezes: ~210 (county normal, NOAA 1991–2020 Climate Normals)
- County Land Area: 288K acres (US Census TIGER 2025)
Zone data: USDA ARS Plant Hardiness Zone Map 2023. Climate data: NOAA NCEI. County boundaries: US Census TIGER/Line 2025.
Frost dates here are the Sullivan County average. Low spots and tree cover move them by days on any one yard — see your exact frost windows.
Frequently Asked Questions
What hardiness zone is Sullivan County, Pennsylvania?
Sullivan County sits in USDA hardiness zone 6a, per the USDA Plant Hardiness Zone Map 2023. Zones reflect average annual extreme minimum temperatures from 1991–2020 weather data.
Is it too late to plant in Sullivan 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 16; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 13 (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. Here the season winds down slowly: late sowings, a real autumn harvest, and garlic in the ground before the first hard freeze.
When does frost risk typically end in Sullivan County?
The last hard freeze (28°F) in Sullivan County typically lands around Apr 13, per NOAA 1991–2020 climate normals — an earlier marker than the light-frost dates many planting charts quote. That marks the hard freeze, not the last light frost — light frosts can still bite for a few more weeks, so tender transplants usually wait another 2–3 weeks.
How long is the growing season in Sullivan County?
Measured between 28°F hard freezes, Sullivan County sees about 210 frost-free days — roughly Apr 13 through Nov 9, per NOAA 1991–2020 climate normals. Tender crops get a somewhat shorter practical window, since lighter frosts reach a few weeks past the hard-freeze dates on both ends.
What vegetables grow in Sullivan County?
Sullivan County's zone 6a supports a wide range — strong performers include Apple, Tomato, Grape, Mountain Laurel, and Mushroom. What actually takes on any one site comes down to its soil, sun, and drainage, and we score each plant against the real conditions at your address.
Which hardiness zone is Sullivan County, really?
Officially, Sullivan County sits in USDA zone 6a (USDA PHZM 2023) — but a zone is a 30-year average of winter's coldest night across an area, and it can't see any one yard. A south-facing slope, a tree line, or a low frost pocket can shift a single site by half a zone either way, which is why neighboring gardeners often quote different numbers. We read the conditions at your exact address — soil, sun, slope, and frost — and score 1,112 plants against what's actually there.
Is the soil safe to grow vegetables in Sullivan County?
The federal record around Sullivan County shows 123 documented sites — 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.
Just moved to Sullivan County — what should I know before planting?
Start with three facts. Sullivan County sits in USDA zone 6a, which sets what survives winter; the last 28°F hard freeze typically clears around Apr 13, with about 210 frost-free days to work with (NOAA 1991–2020 climate normals); and 123 documented sites sit on the federal record — a typical footprint for a growing area, worth a look on the contamination map before food beds. From there, matching plants to your actual soil and sun is the fun part.
Everything on this page is a Sullivan County average. Your yard writes its own version — 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.