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When to Plant Onion in Mitchell County, NC

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.

Mitchell County, North Carolina is in USDA Zone 7a. The average last spring frost is April 16 and the first fall frost is October 22, giving you a growing season of approximately 189 days.

At an elevation of 3,527 feet, Mitchell County receives approximately 47.7 inches of rainfall annually with predominantly clay loam soil. Summer highs average 85°F, providing good warmth for Onion during the growing season. Clay soil retains moisture well for Onion, but amend with compost to improve drainage and prevent root rot.

Mitchell County, NC (Zone 7a) Moderate season
189 days
Last Spring Frost April 16
189 growing days
First Fall Frost October 22

Mitchell County Soil Profile

Soil Type

Clay Loam

Soil pH

6.0-7.0

Drainage

Well Drained

Onion Planting Timeline — Mitchell County, NC

Onion Planting Calendar

Activity When Date Range
Start Indoors March 12 Mar 12 – Mar 26
Transplant Outdoors April 16 Apr 16 – Apr 30
Direct Sow April 2 Apr 2 – Apr 23
Harvest July 16 Jul 16 – Sep 3
Fall Sowing August 13 Aug 13 – Aug 27

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

Month-by-Month Timeline

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

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 7a

📆 Growing Season

189 days in Mitchell County

Growing Tips for Mitchell 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 Mitchell County, NC?

Mitchell County is in Zone 7a with an average last frost of April 16. Plan your Onion planting based on this frost date — see the calendar above for exact timing.

What planting zone is Mitchell County, NC?

Mitchell County, North Carolina is in USDA Hardiness Zone 7a. The average last spring frost is April 16 and first fall frost is October 22.

🌱

Your Mitchell County Garden Planner — Free

A 22-page printable planner built for Mitchell County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

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

Sources & credits

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