Kiawah Island, South Carolina, sits in USDA hardiness zone 9a — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
Crops well matched to these conditions include artichoke, fig, california poppy, and cabbage — though what thrives on any one site still turns on its specific soil, sun, and drainage.
Even in Kiawah Island, no two yards are alike.
A low spot, a south-facing slope, or a stand of trees moves the frost date and sun across a single Kiawah Island lot. 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 Kiawah Island — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Kiawah Island — the short answer
Kiawah Island, South Carolina: USDA zone 9a, about 320 days between hard freezes, across 7K acres of town.
- USDA zone
- 9a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Feb 1
- Charleston County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 18
- Charleston County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~320
- Charleston County normal — NOAA 1991–2020, nearest to this town
- Town area
- 7K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. No 30-year normal resolves at this town’s own centroid, so the hard-freeze dates are Charleston County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 9a is Kiawah Island's average, not your lot's — a low corner or a tree line moves it. Against Kiawah Island's 320-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Kiawah Island
Each reading below is measured for Kiawah Island itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsKiawah Island runs about 320 days between hard freezes (read from Charleston County, the closest normal to Kiawah Island) — 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
MeasuredKiawah Island 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 Kiawah Island is in
Kiawah Island sits in the Southern Coastal Plain — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Kiawah Island's own centroid rather than borrowed from Charleston County.
What Grows in Kiawah Island
Every plant below cleared Kiawah Island's own zone 9a and its 320-day season. Each card opens that plant's South Carolina profile. How we score.
Is it too late to plant in Kiawah Island?
Rarely: the season closes in stages, not all at once, and each stage has its crops. 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. In a climate this gentle, “too late” hardly applies — the question becomes which crops prefer the cooler months ahead.
Documented around Kiawah Island
Survey cells within 31 miles of Kiawah Island checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 168 miles off. What to watch for.
What's on the federal record near Kiawah Island
Closest first, within ~10 miles of Kiawah Island. Listing isn't leaking, and distance isn't exposure.
- OSPREY POINT GOLF COURSE MAINTENANCEUnderground Storage Tanks · 2600 ft
- MARSH POINTUnderground Storage Tanks · 1.5 mi
- ST JOHNS FIRE STATION 4Underground Storage Tanks · 2.8 mi
- CSX TRANSPORTATION, INCBrownfields · 3.4 mi
- CESSCO INCToxics Release Inventory · 3.8 mi
- CESSCO INC.Brownfields · 3.8 mi
- CESSCO INC.Toxics Release Inventory · 3.8 mi
- AGFEE DIVISION BAYER CORPORATION C O KIAWAH ISL RESBrownfields · 4.0 mi
- HOWELL'S STOREUnderground Storage Tanks · 4.1 mi
- BLUE WATER 11Underground Storage Tanks · 4.1 mi
- ISLAND PICKUPUnderground Storage Tanks · 4.2 mi
- GREENS EXXONUnderground Storage Tanks · 4.8 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Kiawah Island'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 Kiawah Island.
Total Sites
97
within ~10 miles of Kiawah Island
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Kiawah Island
Severity Distribution
within ~10 miles of Kiawah Island
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Kiawah Island, two things run higher than the national average within ~10 miles of Kiawah Island — PFAS (3 sites) and Underground Storage Tanks (65 sites). That's not a problem with your land — it's information about it.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Kiawah Island
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 Kiawah Island average
Your land is one point inside Kiawah Island
Everything above resolves to Kiawah Island as a whole — one PHZM band, read across 7K acres, with hard-freeze dates borrowed from Charleston County’s record because no 30-year normal resolves at this town’s own centroid. 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 town 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 local average.
Your Lot vs the Kiawah Island Average
Kiawah Island Average
- ●USDA Zones 9a, averaged across Kiawah Island
- ●One soil character for all of Kiawah Island
- ●Frost dates read at Kiawah Island's scale: Feb 1 to Dec 18
YOUR Parcel
- ✓Your exact zone, not Kiawah Island's 9a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Kiawah Island
Pull a site-specific report for your exact address in Kiawah Island, South Carolina — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Kiawah Island averages can't show:
We read public map data around Kiawah Island — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Kiawah Island average
How we know this about Kiawah Island
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this town’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Charleston County’s record, because none resolves here; boundaries and acreage from US Census TIGER/Line 2025; the contamination records from the federal sources named in their beats above. Soil is not read at town grain anywhere on this page — there is no town-resolution survey in our data, which is why you will find no soil grid here rather than a statewide one wearing a local label. The resolution ledger below names every figure this page inherited.
Common questions about Kiawah Island
When does frost risk typically end in Kiawah Island?
The last hard freeze (28°F) in Kiawah Island 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.
When is the first frost in Kiawah Island?
The first hard freeze (28°F) in Kiawah Island typically arrives around Dec 18, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Dec 4, so the watching starts about Nov 18 — about 320 days after the spring freeze cleared.
How long is the growing season in Kiawah Island?
Measured between 28°F hard freezes, Kiawah Island 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 Kiawah Island?
The federal record around Kiawah Island is a meaningful one — 97 documented sites, mostly Underground Storage Tanks entries (65), the nearest Underground Storage Tanks record about 0.5 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.
How do I protect my plants from frost in Kiawah Island?
From about Nov 18 the job here turns from planting to protecting — the last start even a 30-day crop can finish. As the season closes around the first 28°F hard freeze near Dec 18 (NOAA 1991–2020 climate normals), three moves buy time: row cover or an old sheet over tender plants on still, clear nights; water the soil the afternoon before a freeze, so it holds warmth overnight; and harvest tomatoes, peppers and basil before Dec 18. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Kiawah Island's scale — its 9a band and its 320-day season. Your yard writes its own version of Kiawah Island's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
What this page reads at Kiawah Island’s own scale
6 of the readings below were taken at Kiawah Island's own scale — the 7,149 acres it covers and 97 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Kiawah Island's own USDA hardiness band, zones 9aUSDA PHZM 2023
- 97 documented contamination sites on the federal record near Kiawah Island, the closest Underground Storage Tanks record about 0.5 miles out from the town centreFederal environmental registers
- Kiawah Island's boundary and the 7,149 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 ecoregion at Kiawah Island's own centroid, the Southern Coastal PlainUS EPA Level III Ecoregions
- Lanternfly survey cells around Kiawah Island checked, none carrying a detectionlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- The 28°F hard-freeze dates — Kiawah Island has no normal of its own, so its county's is the closest measured readfrom Charleston County
- Soil character — no town-scale survey exists, so Kiawah Island's 7,149 acres read through its county's SSURGO summaryfrom Charleston County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Charleston County
- The growing challenges every South Carolina grower plans around — written at state scale, so they stay on the state guidefrom South Carolina
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Charleston County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Kiawah Island's 7,149 acreswhy one lot differs from the next →
- Which side of Kiawah Island you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 7,149 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.5 miles out, measured from the town centrehow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — measured at your address, and averaged away by any Kiawah Island-wide figureread your own land →