Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 29, 2026

Planting zone for 29817 — Blackville, SC

ZIP code 29817 (Blackville, Barnwell County) is in USDA zone 8b: the coldest winter night averages 15 to 20 °F. The median last spring frost is March 20 and the first fall frost November 13.

Where ZIP 29817 is

Outlined: the ZIP code area · tap the map for the zone at any spot · scroll or pinch to zoom

Not the official USDA Plant Hardiness Zone Map. Zones come from the 2023 USDA hardiness-zone data by the PRISM Group, Oregon State University; we re-mapped and recolored them. The official map is at planthardiness.ars.usda.gov.

Zone8b15 to 20 °F

Coldest night−9.4 to −6.7 °C

Last frostMar 20

First frostNov 13

2012 zone8a

Was 8a on the 2012 map — half a zone warmer now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 8b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Blackville, SC…

Forecast data: National Weather Service (api.weather.gov), public domain. This is not a warning service — for official frost and freeze warnings see weather.gov.

Frost dates in Blackville, SC

JanFebMarAprMayJunJulAugSepOctNovDec

Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free

Last spring frostMarch 20median — 50% chance of a later frost

Safe for tender plantsApril 8only 10% chance of frost after

First fall frostNovember 13median — 10% chance by Oct 29

Growing season238 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 5 and returns around November 30.

From the NOAA station Blackville 3 W, SC — 4 miles away, elevation 318 ft. NOAA NCEI U.S. Climate Normals 1991–2020, 32 °F threshold. Low spots and valleys can freeze later in spring than the station.

When to plant vegetables in 29817

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Feb 6 – Feb 20

SpinachSow outdoors · Feb 6 – Feb 27

Broccoli, cabbageStart indoors · Jan 9 – Jan 23

Broccoli, cabbageTransplant · Feb 27 – Mar 13

Onion setsPlant outdoors · Feb 20 – Mar 6

PotatoesPlant outdoors · Feb 27 – Mar 13

LettuceSow outdoors · Feb 20 – Mar 6

Carrots, beetsSow outdoors · Feb 27 – Mar 13

TomatoesStart indoors · Jan 23 – Feb 6

TomatoesTransplant · Mar 27 – Apr 10

Peppers, eggplantStart indoors · Jan 9 – Jan 23

Peppers, eggplantTransplant · Apr 3 – Apr 17

BeansSow outdoors · Mar 27 – Apr 10

Sweet cornSow outdoors · Mar 27 – Apr 10

Cucumbers, squashSow outdoors · Mar 27 – Apr 10

Fall lettuce, spinachSow outdoors · Sep 18 – Oct 2

GarlicPlant cloves · Oct 30 – Dec 4

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Mar 20) and first fall frost (Nov 13) with the rules of thumb U.S. extension services publish. Cool-season crops take a light frost; warm-season crops do best once the soil is above about 60 °F.

When spring arrived in 2026

In 2026, spring leaf-out near 29817 came on Feb 14 — 10 days later than the 1991–2020 average (Feb 4).

average
Feb 42026
Feb 14

JanFebMarAprMayJun

The Spring Index marks the day when accumulated warmth is enough for lilac and honeysuckle to leaf out — a widely used signal that the growing season has started. Source: USA National Phenology Network, www.usanpn.org — Spring Indices, first leaf, 2026 (data as of 2026-09-08) and 30-year average 1991–2020 (CC BY 4.0).

Native plants for zone 8b in South Carolina

566 plants native to the lower 48 states, recorded in South Carolina, and rated by the USDA to survive 15 °F or colder — the bottom of zone 8b. Each links to its USDA PLANTS profile.

Source: USDA, NRCS. 2026. The PLANTS Database (plants.usda.gov), National Plant Data Team — state distribution, native status and the “Temperature, Minimum” characteristic. Check light, moisture and soil needs before buying; local nurseries and your state native plant society can confirm what thrives in Blackville, SC.

Soil in Blackville, SC

The soil mapped at the center of ZIP 29817 is Wagram — sand, well drained.

TextureSanddrains and warms fast; dries out and needs more feeding

pH5.3strongly acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter1.25%low — add compost

Hydrologic groupAwater soaks in fast

Farmland classFarmland of statewide importanceUSDA classification

Map unit: Wagram sand, 2 to 6 percent slopes.

Soil Survey Staff, Natural Resources Conservation Service, USDA. Soil Survey Geographic (SSURGO) Database, via Soil Data Access, accessed 2026-10-29. The soil at the center point of ZIP 29817; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Blackville, SC

Summer high91 °Faverage high, July

Winter low36 °Faverage low, January

Hot days63days a year at 90 °F or more

Freezing nights39nights a year at 32 °F or less

Growing degree days5,629base 50 °F — the season’s usable heat

Longest day14 h 22 mindaylight on June 21

Shortest day9 h 56 mindaylight on December 21

Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully

Precipitation46.2 inper year, rain and melted snow

Average high and low, by month

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Blackville 3 W, SC (4 mi away); precipitation: Blackville 3 W, SC (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 8b.

Williston, SC · 10 mi

291468b

Springfield, SC · 10 mi

South Carolina planting zones →

Questions about 29817

What planting zone is ZIP code 29817?

ZIP code 29817 (Blackville, SC) is in USDA hardiness zone 8b on the 2023 map: the coldest night of an average winter reaches 15 to 20 °F (−9.4 to −6.7 °C).

When is the last frost in Blackville, SC?

The median last spring frost (32 °F) near 29817 is March 20; after April 8 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Blackville 3 W station.

When is the first frost in Blackville, SC?

The median first fall frost near 29817 is November 13, giving a median frost-free growing season of 238 days.

When should I plant tomatoes in 29817?

Start tomato seeds indoors around Jan 23 – Feb 6 and set transplants outside around Mar 27 – Apr 10, one to three weeks after the median last frost.

How much rain and snow does 29817 get?

About 46.2 inches of precipitation a year (NOAA 1991–2020 normals, Blackville 3 W station).

How hot do summers get in Blackville, SC?

The average high peaks at 91 °F in July, with about 63 days a year at 90 °F or more.

What kind of soil does 29817 have?

The USDA soil survey maps Wagram at the center of ZIP 29817: sand, well drained, pH about 5.3 (strongly acidic).

Did spring come early in Blackville, SC in 2026?

Spring leaf-out near 29817 came on Feb 14 in 2026, 10 days later than the 1991–2020 average (Feb 4), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Blackville, SC?

Intermediate onions: the longest day near 29817 is 14 h 22 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 29817 change?

Yes. The 2012 USDA map put 29817 in zone 8a; the 2023 map puts it in zone 8b. The newer map uses 1991–2020 data and more weather stations.