kabocha squash (Cucurbita maxima Kabocha Group), photographi

Can I Grow Kabocha Squash in South Carolina?

USDA Zones 7a-9b · Plant zone range 3-11

Yes — Strong Match

kabocha squash (zones 3-11) covers every zone South Carolina contains (7a-9b), so hardiness is not what limits it anywhere in the state.

Kabocha Squash in South Carolina — the short answer

Kabocha Squash in South Carolina: hardy in zones 3–11, full sun, against a state median of ~265 frost-free days.

Plant zones
3-11
Manual horticultural correction (source not retained); NC State Extension and Missouri Botanical Garden, with the remaining rows from other published sources or Growable Ground compilation
South Carolina zones
7a-9b
USDA PHZM 2023
Frost window
Feb 27 - Mar 12 – Nov 23 - Dec 1
NOAA RCC ACIS 1991-2020, 28°F
Shortest county season
237 days
NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
Days to maturity
95 days
Growable Ground Plant Database

Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS and university Extension sources — per-field provenance varies and is published with the dataset.

Score your parcel · free

Your yard isn't the whole zone.

South Carolina spans zones 7a-9b, but your yard has its own microclimate — slope, trees, and low spots shift frost and sun across a single parcel. Enter your address and we'll score kabocha squash 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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South Carolina is not one climate

A single South Carolina answer averages 46 counties whose growing seasons are 83 days apart — from 237 frost-free days in Chester County to 320 in Charleston County. Which end of that your land sits nearer changes what kabocha squash can finish before the first hard freeze.

237 daysChester County320 daysCharleston County

The middle half of 46 counties runs 256277 days, with a median of 264 days — a 83-day span end to end.

Measured across 46 South Carolina counties. NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze. Quartiles are order statistics — every figure shown is a value a real county recorded, not an interpolation. Your own site sits somewhere inside this range; a parcel report resolves where.

Where in South Carolina Fits Best

Even within South Carolina's zones 7a-9b, county microclimates differ enough to change what thrives. These counties carry the closest zone match for kabocha squash (USDA PHZM 2023):

Zone Comparison

Kabocha Squash Needs

  • USDA Zones: 3-11
  • Frost-Free Days: 80+
  • Sun: Full Sun
  • Mature size: 2 ft tall
  • Picking window: ~14 days of harvest
  • Drought tolerance: Low

South Carolina Has

  • USDA Zones: 7a-9b
  • Last Hard Freeze (28°F): Feb 27 - Mar 12
  • First Hard Freeze (28°F): Nov 23 - Dec 1
  • Annual Rainfall: 45-55 inches
  • Common Soils: Red clay (Piedmont), Sandy loam (Coastal), Alluvial

Plant Zone Range (zones 3-11)

3a
11b
3a (Cold)13b (Hot)

Preferred Soil pH

3.5 (Acidic)7.0 (Neutral)9.0 (Alkaline)
Highlighted range: pH 5.08.5

Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS, and university Extension sources — per-field provenance varies and is published with the dataset. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.

When to Plant Kabocha Squash in South Carolina

The frost window

Across South Carolina, the last spring hard freeze (28°F) clears between Feb 27 and Mar 12, and the first fall hard freeze lands between Nov 23 and Dec 1 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 256-day window you can count on — up to 277 days on a mild site in a kind year. That marks the hard freeze, not the last light frost, so tender transplants usually wait another 2-3 weeks.

When to start the seed

Those dates are when kabocha squash goes out, not when it starts. It is sown under cover about 3 weeks ahead, so counting back from South Carolina's late-side last freeze of Mar 12 is what fixes your sowing date — and a yard that clears frost earlier than the state's late date starts earlier still.

Days to maturity vs. the window

At 95 days to maturity (Growable Ground Plant Database), counting from the last hard freeze it ripens with 161 days to spare even in South Carolina's tightest freeze scenario — room for a later start or a second sowing.

Frost window: NOAA Climate Normals 1991-2020. Plant timing fields: Growable Ground Plant Database — frost-free days from FAO ECOCROP, days to harvest from university Extension production guides, and growing-degree-day and chill-hour minimums that are compilation estimates rather than published figures. Your site's own frost dates can run earlier or later than the state range — a parcel report pins them down.

Growing Season Fit

The zone check says kabocha squash survives winter here. Whether the season is long enough — and warm enough — is a different question.

Frost-free days

Kabocha Squash wants 80+ frost-free days; a typical South Carolina site sees ~265 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves comfortable headroom for succession planting.

Growing degree days

Kabocha Squash needs ~2200 GDD (base 50°F) to ripen. The state median runs ~5233 GDD (from PRISM 1991-2020 climate normals), so South Carolina's typical season clears that easily.

GDD and chill-hour figures are computed from PRISM 1991-2020 monthly climate normals; frost-free days from NOAA Regional Climate Centers ACIS, 1991-2020. Each is the state median across its counties (P25/P75 span the within-state spread). Hardiness-zone range is USDA PHZM 2023.

Soil + Drainage Fit

Kabocha Squash tolerates a wide pH range (pH 5-8.5) — 3.5 units, acid ground through alkaline — so soil acidity is rarely what limits it in South Carolina. A soil test is still worth having, but for what else it tells you about this site, not to clear this plant. It will grow across that whole span, but it does best between pH 5.5 and 7.5 — worth knowing before you decide whether a South Carolina soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your South Carolina site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.

Plant pH requirements: FAO ECOCROP and USDA PLANTS, with the remaining rows from other published sources or Growable Ground compilation. Drainage: FAO ECOCROP, with the remaining rows from other published sources or Growable Ground compilation. South Carolina soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.

Before you plant kabocha squash for food

Anything you grow to eat takes up what is in the ground it grows in, so what is on record near you is worth knowing before kabocha squash goes in. What follows is South Carolina’s documented federal record at state scale — a screening signal, not a soil test, and not a statement about any one lot.

Safe to Grow Here?

What the federal record shows across South Carolina — and how to grow with it.

Federal record: High

We checked the federal record across South Carolina24,910 documented sites across 7 of the 9 source types we track.

The most significant on record: 256 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.

South Carolina 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.

Know before you grow — the guide

Sources Checked

across South Carolina

Severity Distribution

across South Carolina

High148Moderate7,159Low17,603

Highest-Severity Sites

PFAS Sampling · PFAS Detected
PFAS Sampling · PFAS Detected
PFAS Sampling · PFAS Detected
Superfund · Superfund NPL
PFAS Sampling · PFAS Detected

A note from Gnorman

What an experienced grower watches for around here

In and around South Carolina, Toxics Release Inventory runs higher than the national average — 1,600 sites across South Carolina. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.

Toxics Release Inventory: TRI facilities report annual chemical releases to air, water, and land.

Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.

grow under coverread your soil before you plant

Sources: EPA, USGS1.8M documented sites tracked nationwide across 9 federal source types.

What Else to Consider for Kabocha Squash in South Carolina

Zone compatibility tells you about winter cold survival — but South Carolina growers also need to think about:

Red Piedmont clay requires amendment for drainage

High heat and humidity promote diseases

Hurricane risk along the coast

What to actually do about these — and the constraints that apply to every South Carolina grower, not just kabocha squash — is covered on the South Carolina growing guide.

Timing shifts within South Carolina

Kabocha Squash needs about 80 days of frost-free season to complete its cycle. Even Chester County — South Carolina’s shortest season at 237 frost-free days — clears that by 157 days, so season length isn’t the constraint anywhere in South Carolina. What varies is your own parcel.

Across South Carolina’s 46 counties the frost-free season runs from 237 days in Chester County to 320 days in Charleston County — a spread of 83 days, which is why a single statewide planting date misleads. The median South Carolina county sees 265 frost-free days, leaving kabocha squash about 185 days of slack on a typical parcel — room for a second sowing where the season runs long.

County last-freeze dates and frost-free day counts: NOAA Regional Climate Centers ACIS (1991-2020), county 28°F freeze (earlier than the folk 32°F "last frost"). Kabocha Squash's 80-day requirement: USDA PLANTS / Growable Ground plant database (minimum frost-free days). A parcel report resolves your address's own frost dates.

Pollinator + Wildlife Value

Kabocha Squash draws honeybees and native bees (moderate value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, kabocha squash can only work that bloom inside South Carolina's frost window — roughly 265 days, opening after the last 28°F freeze (Feb 27 - Mar 12) and closing at the first (Nov 23 - Dec 1), per NOAA Regional Climate Centers ACIS, 1991-2020.

South Carolina Cooperative Extension

For South Carolina-specific cultivar recommendations, planting calendars, and pest pressure for kabocha squash, the canonical source is Clemson Cooperative Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.

Common Questions About Growing Kabocha Squash in South Carolina

When can I plant Kabocha Squash in South Carolina?

South Carolina's last spring hard freeze (28°F) clears between Feb 27 and Mar 12, and the first fall hard freeze lands between Nov 23 and Dec 1 (NOAA Regional Climate Centers ACIS, 1991-2020). Time outdoor planting to after the last hard freeze for your specific site — a further two to three weeks for anything tender — and count back from those dates for transplant scheduling.

Can Kabocha Squash mature before first frost in South Carolina?

Yes — Kabocha Squash matures in 95 days (Growable Ground Plant Database), and South Carolina's dependable hard-freeze-free window runs 256 days (NOAA Regional Climate Centers ACIS, 1991-2020), leaving 161 days of margin. Plant once the last hard freeze has passed — two to three weeks later for anything tender — and it ripens ahead of the first fall freeze.

What hardiness zone is Kabocha Squash grown in across South Carolina?

South Carolina spans USDA hardiness zones 7a-9b (USDA ARS PHZM 2023). Kabocha Squash carries a range of zones 3-11, so the overlap zones are where outdoor growing is most reliable.

How many frost-free days does a typical South Carolina site have?

A typical South Carolina site sees ~265 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Kabocha Squash needs 80+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date.

How should I amend the soil for Kabocha Squash in South Carolina?

Kabocha Squash tolerates pH 5-8.5 and well (dry spells) drainage (FAO ECOCROP). That is a 3.5-unit span, acid ground through alkaline, so pH is rarely what limits this plant on a South Carolina site — amend for drainage and organic matter first.

Will Kabocha Squash actually grow on my specific land in South Carolina?

State-level zone + climate data is a sketch. A Growable Ground parcel report scores kabocha squash against your address's exact soil pH, drainage, sun, and frost-date data drawn from USDA SSURGO, NOAA, and PRISM — not state averages.

Free Report

Check your specific parcel in South Carolina

State-level data is a sketch. Your Growable Ground report scores kabocha squash against your parcel's exact soil, sun, drainage, and frost data — not zone averages.

Three things about your lot that South Carolina kabocha squash averages can't show:

Your soil pHYour frost-free days — South Carolina averages 265Your sun & shade

We read public map data around South Carolina — soil, climate, flood, and parcel records. How we handle your address.

25+ data sources read at your address, not the South Carolina kabocha squash average

Explore More

Explore South Carolina county by county

South Carolina carries 46 counties with their own USDA zone — a sample of the growing pages for kabocha squash there:

Where else kabocha squash grows

Kabocha Squash's zone band crosses state lines — these are the states closest to South Carolina in winter climate where it also has a page, plus the far ends of its range. Each one re-answers the question with that state's own record.

More to grow in South Carolina

South Carolina has a growing page for 1,034 plants — a rotating sample of the rest of the shelf.

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