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When to Plant Scallions in Charleston County, SC

Scallions (green onions) are mild-flavored alliums harvested for their slender green tops and white bases. They are quick-growing and perfect for succession planting.

Charleston County, South Carolina is in USDA Zone 8b. The average last spring frost is March 6 and the first fall frost is November 17, giving you a growing season of approximately 256 days.

At an elevation of 275 feet, Charleston County receives approximately 48.1 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 95ยฐF, so Scallions may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring โ€” great for early planting โ€” but Scallions will need more frequent watering and organic matter to retain nutrients.

Charleston County, SC (Zone 8b) Long season
256 days
Last Spring Frost March 6
256 growing days
First Fall Frost November 17

Charleston County Soil Profile

Soil Type

Sandy Loam

Soil pH

5-6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (179 days to spare)
Start indoors: Jan 16 Transplant: Feb 20 🍅 Harvest: Apr 17 – May 15
Recommended (50%) ✓ Fits season (172 days to spare)
Start indoors: Jan 30 Transplant: Mar 6 🍅 Harvest: May 1 – May 29
Safe Start (90%) ✓ Fits season (172 days to spare)
Start indoors: Feb 22 Transplant: Mar 29 🍅 Harvest: May 24 – Jun 21

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
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 480 gal / 100 sq ft
Scallions needs ~1,275 GDD — county provides 5,440 GDD Excellent fit

Scallions Planting Timeline โ€” Charleston County, SC

Scallions Planting Calendar

Activity When Date Range
Start Indoors January 30 Jan 30 โ€“ Feb 13
Transplant Outdoors March 6 Mar 6 โ€“ Mar 20
Direct Sow February 20 Feb 20 โ€“ Mar 13
Fall Sowing September 8 Sep 8 โ€“ Sep 22
Harvest May 1 May 1 โ€“ May 29

Plant 0.5" deep ยท 6" apart ยท Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

50โ€“70 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 8b

Growing Season

256 days

Growing Tips for Charleston County

Direct sow every 3 weeks for continuous harvest. Thin to 1 inch apart or grow in clusters. Harvest when pencil-thick by pulling or cutting at soil level.

Companion Planting

Good Companions

Avoid Planting Near

  • Peas
  • Green Beans

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Frequently Asked Questions

When should I plant Scallions in Charleston County, SC?

Charleston County is in Zone 8b with an average last frost of March 6. Plan your Scallions planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Charleston County, SC?

Charleston County, South Carolina is in USDA Hardiness Zone 8b. The average last spring frost is March 6 and first fall frost is November 17.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Charleston County gardeners in Zone 8b 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 Charleston County, SC. Local conditions may vary. Last updated: April 2026.