Union County, in South Carolina, sits in USDA hardiness zone 8a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
On paper, peach, okra, muscadine grape, and palmetto all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Union County lies within the Piedmont — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Union County holds more than one microclimate.
Soils and elevations shift across Union 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
8a
Last Hard Freeze (28°F)
Jan 30
County normal — light frosts run a few weeks later
First Frost (state avg.)
Oct 20 - Nov 20
County Area
329K acres
Hardiness Zone Range
Growing Season (statewide frost window)
Zone maps are averages across Union County. Your yard's slope, trees, and frost pockets shift what actually grows — see your land's exact reading.
Soil in Union County
Across Union County, the ground is predominantly Ultisols, where Madison, Wilkes, and Cecil are the most extensive named soil series. The soil is generally well drained with a sandy loam surface. Topsoil pH runs about 5.3–6.0, moderately acidic. Rainfall drains through hydrologic group B soils.
Soil order
Ultisols
Drainage
Well drained
Prime farmland
9%
Hydric soils
2%
Soil still varies lot by lot — soil types explained.
What Grows in Union County
Plants matched to Union County's USDA zones 8a — each links to its full growing profile.
Growing Challenges in South Carolina
What an experienced grower plans around here — each one has a move.
Red Piedmont clay requires amendment for drainage
Compost opens red clay over time; a raised bed opens it today — both together is the Piedmont standard.
High heat and humidity promote diseases
Wide spacing, morning base-watering, and resistant varieties keep the humid summer honest — extension keeps the lists.
Hurricane risk along the coast
Coastal beds favor wind-tough perennials and well-staked young trees before the storm season.
For cultivar selection, pest pressure, and planting-time guidance specific to South Carolina, the Clemson Cooperative Extension is the authoritative local source.
Safe to Grow Here?
What the federal record shows across Union County — and how to grow with it.
We checked the federal record across Union County — 171 documented sites across 6 of the 9 source types we track.
The most significant on record: 17 Toxics Release Inventory facilities. Active industrial facilities reporting chemical releases to air, water, and land.
The federal record across Union 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
171
across Union County
Risk Level
Moderate
Highest-severity
17 Toxics Release Inventory facilities
Sources Checked
across Union County
Severity Distribution
across Union County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Union County, two things run higher than the national average — Toxic Release Inventory (17 sites) and Underground Storage Tanks (110 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Toxic 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 Union 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
Union County Average
- ●USDA Zones 8a
- ●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 Union County
Pull a site-specific report for your exact address in Union County, South Carolina — 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 Union County, South Carolina
- USDA Hardiness Zones: 8a (USDA PHZM 2023)
- Last Hard Freeze (28°F): Jan 30 (county normal, NOAA 1991–2020 Climate Normals — light frosts can follow for a few weeks)
- First Fall Frost (state avg.): Oct 20 - Nov 20 (NOAA 30-Year Climate Normals)
- County Land Area: 329K 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 Union 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 Union County, South Carolina?
Union County sits in USDA hardiness zone 8a, per the USDA Plant Hardiness Zone Map 2023. Zones reflect average annual extreme minimum temperatures from 1991–2020 weather data.
When does frost risk typically end in Union County?
The last hard freeze (28°F) in Union County typically lands around Jan 30, 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.
What vegetables grow in Union County?
Union County's zone 8a supports a wide range — strong performers include Peach, Okra, Muscadine Grape, Palmetto, and Fig. 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 Union County, really?
Officially, Union County sits in USDA zone 8a (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 Union County?
The federal record around Union County shows 171 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 Union County — what should I know before planting?
Start with three facts. Union County sits in USDA zone 8a, which sets what survives winter; the statewide frost window runs about Mar 1 - Apr 10 to Oct 20 - Nov 20 (NOAA 30-year climate normals); and 171 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 Union 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 South Carolina's frost window, season length, and soil profile against the plant's real requirements.