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When to Plant Onion in Berkeley County, SC

Berkeley County, South Carolina Zone 8b May

Your May planting checklist for Berkeley County, South Carolina

May is a pivotal month for Berkeley County, South Carolina gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost February 29
Avg. first frost November 23
Soil temp (4") 72°F
Watering Low
Pest pressure High
Daylight 13.7 hrs

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Onions are a fundamental kitchen staple available in yellow, white, and red varieties. Choose long-day, short-day, or intermediate types based on your latitude.

Berkeley County, South Carolina is in USDA Zone 8b. The average last spring frost is March 1 and the first fall frost is November 23, giving you a growing season of approximately 267 days.

At an elevation of 441 feet, Berkeley County receives approximately 52.8 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 93°F, providing good warmth for Onion during the growing season. Sandy soil warms quickly in spring — great for early planting — but Onion will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Onion root diseases.

Berkeley County, SC (Zone 8b) Long season
267 days
Last Spring Frost March 1
267 growing days
First Fall Frost November 23
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Berkeley County Soil Profile

Soil Type

Sandy Loam

Soil pH

6.0-7.0

Drainage

Well Drained

Onion Planting Timeline — Berkeley County, SC

Onion Planting Calendar

Activity When Date Range
Start Indoors January 25 Jan 25 – Feb 8
Transplant Outdoors March 1 Mar 1 – Mar 15
Direct Sow February 15 Feb 15 – Mar 8
Harvest May 31 May 31 – Jul 19
Fall Sowing September 14 Sep 14 – Sep 28

Plant 1" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 8b

📆 Growing Season

267 days in Berkeley County

Growing Tips for Berkeley County

Start seeds indoors 8-10 weeks before transplanting. Match day-length type to your latitude. Stop watering when tops begin to fall over and cure bulbs for 2-3 weeks before storage.

Companion Planting

Good Companions

Avoid Planting Near

  • Peas
  • Green Beans
  • Asparagus

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Onion in Berkeley County, SC?

Berkeley County is in Zone 8b with an average last frost of March 1. Plan your Onion planting based on this frost date — see the calendar above for exact timing.

What planting zone is Berkeley County, SC?

Berkeley County, South Carolina is in USDA Hardiness Zone 8b. The average last spring frost is March 1 and first fall frost is November 23.

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Your Berkeley County Garden Planner — Free

A 24-page printable planner built for Berkeley County (Zone 8b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Berkeley County, SC. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.