Sullivan County, in Tennessee, sits in USDA hardiness zone 7b — 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 tomato, pawpaw, iris, and muscadine grape; 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.
No card required · your full report in seconds
Quick Facts
USDA Zones
7b
Last Hard Freeze (28°F)
Feb 26
County normal — light frosts run a few weeks later
First Hard Freeze (28°F)
Nov 29
County normal — light frosts arrive a few weeks earlier
County Area
265K 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 Ultisols, where Montevallo, Collegedale, and Etowah are the most extensive named soil series. The soil is generally well drained with a silty clay loam surface. Topsoil pH runs about 5.0–5.3, strongly acidic. Rainfall drains through hydrologic group C soils.
Soil order
Ultisols
Drainage
Well drained
Prime farmland
8%
Hydric soils
2%
Soil still varies lot by lot — soil types explained.
What Grows in Sullivan County
Plants matched to Sullivan County's USDA zones 7b — 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 Jan 29; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Feb 26 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 29 — long-season crops need about 90 days of runway, quick greens only 30. With almost year-round growing weather, timing is about heat and rainfall more than frost — some bench is always in play.
Growing Challenges in Tennessee
What an experienced grower plans around here — each one has a move.
Heavy clay soils in the Nashville Basin
Basin clay is fertile once it drains — a raised bed handles that immediately, and yearly compost makes it permanent.
High humidity promotes disease in summer
Morning base-watering, breathing room between plants, and resistant varieties — the humid-summer basics from your extension.
Variable spring weather with late frost risk
Let your local frost normals set the schedule — Tennessee springs reward the growers who wait out the last cold snap.
For cultivar selection, pest pressure, and planting-time guidance specific to Tennessee, the UT 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 — 754 documented sites across 7 of the 9 source types we track.
The most significant on record: 6 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Sullivan County carries one of the heavier federal records we track — and that's not a verdict on your yard. Proximity to a documented site is information, not a diagnosis: nothing here says any particular parcel is affected. It does earn one concrete step — before food beds go in the ground, a professional soil test tells you exactly what you're working with, and raised beds with clean imported soil grow well almost anywhere in the meantime.
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.
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, Underground Storage Tanks runs higher than the national average — 544 sites nearby. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
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 7b
- ●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, Tennessee — 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, Tennessee
- USDA Hardiness Zones: 7b (USDA PHZM 2023)
- Last Hard Freeze (28°F): Feb 26 (county normal, NOAA 1991–2020 Climate Normals — light frosts can follow for a few weeks)
- First Hard Freeze (28°F): Nov 29 (county normal, NOAA 1991–2020 Climate Normals — light frosts can arrive a few weeks earlier)
- Days Between Hard Freezes: ~276 (county normal, NOAA 1991–2020 Climate Normals)
- County Land Area: 265K 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, Tennessee?
Sullivan County sits in USDA hardiness zone 7b, 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 Jan 29; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Feb 26 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 29 — long-season crops need about 90 days of runway, quick greens only 30. With almost year-round growing weather, timing is about heat and rainfall more than frost — some bench is always in play.
When does frost risk typically end in Sullivan County?
The last hard freeze (28°F) in Sullivan County typically lands around Feb 26, 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 276 frost-free days — roughly Feb 26 through Nov 29, 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 7b supports a wide range — strong performers include Tomato, Pawpaw, Iris, Muscadine Grape, and Tulip Poplar. 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 7b (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 runs heavier than most — 754 documented sites — so test the soil before planting food in the ground, and raised beds with clean imported soil grow well in the meantime. Even here, proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what's recorded and where.
Just moved to Sullivan County — what should I know before planting?
Start with three facts. Sullivan County sits in USDA zone 7b, which sets what survives winter; the last 28°F hard freeze typically clears around Feb 26, with about 276 frost-free days to work with (NOAA 1991–2020 climate normals); and 754 documented sites sit on the federal record here, so a soil test before food beds is the smart first step. 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 Tennessee's frost window, season length, and soil profile against the plant's real requirements.