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When to Plant Onion in Guernsey County, OH

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.

Guernsey County, Ohio is in USDA Zone 6b. The average last spring frost is April 30 and the first fall frost is October 16, giving you a growing season of approximately 169 days.

At an elevation of 790 feet, Guernsey County receives approximately 30.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Onion during the growing season.

Guernsey County, OH (Zone 6b) Moderate season
169 days
Last Spring Frost April 30
169 growing days
First Fall Frost October 16

Guernsey County Soil Profile

Soil Type

Silt Loam

Soil pH

6.0-7.0

Drainage

Well Drained

Onion Planting Timeline — Guernsey County, OH

Onion Planting Calendar

Activity When Date Range
Start Indoors March 26 Mar 26 – Apr 9
Transplant Outdoors April 30 Apr 30 – May 14
Direct Sow April 16 Apr 16 – May 7
Harvest July 30 Jul 30 – Sep 17
Fall Sowing August 7 Aug 7 – Aug 21

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
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 6b

📆 Growing Season

169 days in Guernsey County

Growing Tips for Guernsey 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 Guernsey County, OH?

Guernsey County is in Zone 6b with an average last frost of April 30. Plan your Onion planting based on this frost date — see the calendar above for exact timing.

What planting zone is Guernsey County, OH?

Guernsey County, Ohio is in USDA Hardiness Zone 6b. The average last spring frost is April 30 and first fall frost is October 16.

🌱

Your Guernsey County Garden Planner — Free

A 22-page printable planner built for Guernsey County (Zone 6b). 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 Guernsey County, OH. 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.