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When to Plant Sunflower in Clarendon County, SC

Sunflowers are tall, cheerful annuals grown for their edible seeds and as pollinator magnets. They come in sizes from 2-foot dwarfs to 12-foot giants.

Clarendon County, South Carolina is in USDA Zone 8a. The average last spring frost is March 19 and the first fall frost is November 11, giving you a growing season of approximately 237 days.

At an elevation of 291 feet, Clarendon County receives approximately 53.6 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 94ยฐF, providing good warmth for Sunflower during the growing season. Sandy soil warms quickly in spring โ€” great for early planting โ€” but Sunflower will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Sunflower root diseases.

Clarendon County, SC (Zone 8a) Long season
237 days
Last Spring Frost March 19
237 growing days
First Fall Frost November 11

Clarendon County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.1-6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (103 days to spare)
Start indoors: Jan 22 Transplant: Mar 26 🍅 Harvest: Jun 4 – Jul 23
Recommended (50%) ✓ Fits season (104 days to spare)
Start indoors: Jan 29 Transplant: Apr 2 🍅 Harvest: Jun 11 – Jul 30
Safe Start (90%) ✓ Fits season (97 days to spare)
Start indoors: Feb 17 Transplant: Apr 21 🍅 Harvest: Jun 30 – Aug 18

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Sunflower needs ~1,742 GDD — county provides 4,858 GDD Excellent fit

Sunflower Planting Timeline โ€” Clarendon County, SC

Sunflower Planting Calendar

Activity When Date Range
Start Indoors January 29 Jan 29 โ€“ Feb 12
Transplant Outdoors April 2 Apr 2 โ€“ Apr 16
Direct Sow March 26 Mar 26 โ€“ Apr 16
Harvest June 11 Jun 11 โ€“ Jul 30

Plant 1" deep ยท 18" apart ยท Rows 30" apart

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Start Indoors
March Direct Sow
April Transplant Outdoors Direct Sow
May โ€”
June Harvest
July Harvest
August โ€”
September โ€”
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Low โ€” drought tolerant

Days to Maturity

70โ€“100 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 8a

Growing Season

237 days

Growing Tips for Clarendon County

Direct sow after last frost. Stake tall varieties in windy areas. Harvest seed heads when the back turns brown and seeds are plump. Dry heads upside down.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Level Up Your Garden

Frequently Asked Questions

When should I plant Sunflower in Clarendon County, SC?

Clarendon County is in Zone 8a with an average last frost of March 19. Plan your Sunflower planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Clarendon County, SC?

Clarendon County, South Carolina is in USDA Hardiness Zone 8a. The average last spring frost is March 19 and first fall frost is November 11.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Clarendon County gardeners in Zone 8a organize planting dates, track what's growing, and never miss a planting window.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Clarendon County, SC. Local conditions may vary. Last updated: April 2026.