Charleston County, in South Carolina, sits in USDA hardiness zone 9a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Among the crops suited to this profile: artichoke, fig, california poppy, and cabbage. The site-level story — soil, sun, drainage — decides the rest.
Charleston County lies within the Lowcountry and the Sea Islands — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Charleston County holds more than one microclimate.
Soils and elevations shift across Charleston 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 Charleston County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Charleston County — the short answer
Charleston County, South Carolina: USDA zone 9a, about 320 days between hard freezes, across 588K acres.
- USDA zone
- 9a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Feb 1
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Dec 18
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~320
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 588K 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 9a is Charleston County's average, not your lot's — a low corner or a tree line moves it. Against Charleston County's 320-day season, see what your own ground reads.
Heat and winter chill in Charleston County
Across a year, Charleston County accumulates about 5,971 growing degree days above 50°F, about 823 more than the middle South Carolina county — ahead of 43 of South Carolina’s 46 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.
Winter banks about 571 hours below 45°F, 791 fewer than the South Carolina middle of 1,362. Chill is what tells a fruit tree its dormancy is over, and it is set by climate rather than by anything you can build.
Grounded in PRISM Climate Group, Oregon State University — 1991–2020 monthly normals
Soil in Charleston County
Across Charleston County, the ground is predominantly Entisols, where Bohicket, Rutlege, and Wadmalaw are the most extensive named soil series. The soil is generally very poorly drained with a loamy fine sand surface. Topsoil pH runs about 4.7, very strongly acidic. Rainfall drains through hydrologic group A/D soils.
Soil order
Entisols
Drainage
Very poorly drained
Prime farmland
5%
Hydric soils
64%
Soil still varies lot by lot — soil types explained.
How the ground varies across Charleston County
The USDA soil survey maps 36% of Charleston County as very poorly drained — but another 50% drains differently: 18% poorly drained, 16% moderately well drained.
Bohicket is the most extensive named soil at 21% of mapped acres, then Rutlege (9%) and Wadmalaw (7%).
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 Charleston County
Each reading below is measured for Charleston 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 Charleston County are very poorly drained, in hydrologic group A/D — ground that sheds water slowly.
Beds can stay saturated for days after heavy rain, and the roots of most vegetables, berries, and fruit trees suffocate or rot in soil that never drains.
Raised beds or mounded rows lift roots above the wet zone; choose water-tolerant crops for the lowest spots.
USDA NRCS SSURGO
Surface pH
MeasuredTopsoil across Charleston County runs about pH 4.7, 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
MeasuredCharleston County runs about 320 days between hard freezes — close to year-round growing.
Frost is rarely the limit here; winter plantings are as real as summer ones, and the harder question is which crops shrug off the summer heat.
Grow cool-season crops through the mild winter, and choose heat-tolerant varieties for the summer beds.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredCharleston County sits in USDA hardiness zone 9a.
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 Charleston County is in
Charleston County spans 2 EPA Level III ecoregions — Southern Coastal Plain (73%) and Middle Atlantic Coastal Plain (27%). 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 Charleston County
We scored all 1,086 plants against Charleston County's own USDA zone 9a and its own 320-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 South Carolina profile.
Is it too late to plant in Charleston County?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Jan 4; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Feb 1 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 18 — long-season crops need about 90 days of runway, quick greens only 30. And with a calendar this mild, the honest answer is that planting barely stops — winter opens seasons colder regions never see.
Documented around Charleston County
Survey cells within 31 miles of Charleston County checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 155 miles off. What to watch for.
- Japanese beetle2 documented records
- monarch butterfly4,014 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Charleston County
USGS estimates 2,282 lb of 2,4-d on Charleston County farmland in 2019, its largest by weight, ahead of Glyphosate (2,176 lb) and Atrazine (1,635 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 Charleston County — and how to grow with it.
We checked the federal record across Charleston County — 1,778 documented sites across 7 of the 9 source types we track.
The most significant on record: 36 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Charleston 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.
What's on the federal record near Charleston County
Closest first, across Charleston County. Listing isn't leaking, and distance isn't exposure.
- CSX INTERMODAL TERMINALS INCBrownfields · 400 ft
- CHARLESTON CITY OF HOUSING AUTHORITYUnderground Storage Tanks · 500 ft
- PALMETTO SHIPPING & STEVEDORINGUnderground Storage Tanks · 500 ft
- HOPKINS TRANSFER & STORAGE INCUnderground Storage Tanks · 550 ft
- COPLESTON CLEANERSUnderground Storage Tanks · 600 ft
- FAST STOPUnderground Storage Tanks · 600 ft
- EAST SIDE BAPTIST CHURCHUnderground Storage Tanks · 650 ft
- FINA 6812Underground Storage Tanks · 850 ft
- FORMER OLD SERVICE STATIONUnderground Storage Tanks · 1100 ft
- 511 MEETING STREET APARTMENTS SITE IMPROVEMENTSBrownfields · 1200 ft
- FORMER FILLING STATIONUnderground Storage Tanks · 1200 ft
- CHN- 12Nitrate · 1300 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Charleston 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 Charleston County.
Sources Checked
across Charleston County
Severity Distribution
across Charleston County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Charleston County, Superfund runs higher than the national average — 36 sites across Charleston County. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check your specific parcel in Charleston 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 Charleston County average
Your land is one point inside Charleston County
Everything above resolves to Charleston County as a whole — one PHZM band and one county frost record, read across 588K 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 Charleston County Average
Charleston County Average
- ●USDA Zones 9a, averaged across Charleston County
- ●One soil character for all of Charleston County
- ●Frost dates read at Charleston County's scale: Feb 1 to Dec 18
YOUR Parcel
- ✓Your exact zone, not Charleston County's 9a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Charleston County
Pull a site-specific report for your exact address in Charleston County, South Carolina — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Charleston County averages can't show:
We read public map data around Charleston County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Charleston County average
How we know this about Charleston 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 Charleston County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Charleston County
When does frost risk typically end in Charleston County?
The last hard freeze (28°F) in Charleston County typically lands around Feb 1, 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 Feb 22.
How long is the growing season in Charleston County?
Measured between 28°F hard freezes, Charleston County sees about 320 frost-free days — roughly Feb 1 through Dec 18, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Feb 22 to Dec 4, about 285 days.
Is the soil safe to grow vegetables in Charleston County?
The federal record around Charleston County runs heavier than most — 1,778 documented sites, mostly Underground Storage Tanks entries (1,018), the nearest Brownfields record under a tenth of a mile out — 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.
Everything above is measured at Charleston County's scale — its 9a band and its 320-day season. Your yard writes its own version of Charleston 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 South Carolina's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Charleston County’s own scale
9 of the readings below were taken at Charleston County's own scale — its own ~320-day span between 28°F freezes, the 3 most extensive soil series mapped here and 1,778 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Charleston County's own USDA hardiness band, zones 9aUSDA PHZM 2023
- Charleston County's own 28°F hard-freeze dates and its ~320-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Charleston CountyUSDA NRCS SSURGO
- 1,778 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Brownfields record under a tenth of a mile outFederal environmental registers
- Charleston County's boundary and the 587,613 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 9a and a ~320-day seasonGrowable Ground crop-matching engine
- The 2 ecoregions Charleston County spans, Southern Coastal Plain the largestUS EPA Level III Ecoregions
- Open occurrence records documented in Charleston County for 2 tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Charleston County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every South Carolina grower plans around — written at state scale, so they stay on the state guidefrom South Carolina
What this page can’t tell you
- How the season shifts across Charleston County — the ~320 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 Charleston County's 587,613 acreswhy one lot differs from the next →
- Which of those 1,778 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 Charleston Countyread your own land →