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When to Plant Onion in Wood 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.

Wood County, Ohio is in USDA Zone 5b. The average last spring frost is April 27 and the first fall frost is October 21, giving you a growing season of approximately 177 days.

At an elevation of 714 feet, Wood County receives approximately 41.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Onion to ensure they mature before fall.

Wood County, OH (Zone 5b) Moderate season
177 days
Last Spring Frost April 27
177 growing days
First Fall Frost October 21

Wood County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (34 days to spare)
Start indoors: Mar 18 Transplant: Apr 22 🍅 Harvest: Jul 22 – Sep 9
Recommended (50%) ✓ Fits season (37 days to spare)
Start indoors: Mar 23 Transplant: Apr 27 🍅 Harvest: Jul 27 – Sep 14
Safe Start (90%) ✓ Fits season (34 days to spare)
Start indoors: Apr 7 Transplant: May 12 🍅 Harvest: Aug 11 – Sep 29

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.

Soil Compatibility in Wood County

How your county's soil matches Onion's growing requirements.

Soil pH

Your soil pH (5.8โ€“6.8) overlaps with Onion's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

The silt loam soil in Wood County is excellent for Onion โ€” good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Onion.

Organic Matter

Organic matter is excellent (5.2%) โ€” Onion will thrive.

How to Plant Onion

1"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 512 gal / 100 sq ft

Monthly Watering Guide for Onion

Onion needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Onion Needs Rainfall You Supplement Action
Jan โ€” 1.6" 0" โ„๏ธ Dormant
Feb โ€” 2.1" 0" โ„๏ธ Dormant
Mar โ€” 3.3" 0" โ„๏ธ Dormant
Apr 4.3" 3.6" 0.7" ๐Ÿ’ง Light watering
May 4.3" 4.5" 0" โœ… Rainfall sufficient
Jun 4.3" 4.6" 0" โœ… Rainfall sufficient
Jul 4.3" 4.4" 0" โœ… Rainfall sufficient
Aug 4.3" 4.7" 0" โœ… Rainfall sufficient
Sep 4.3" 4.2" 0.1" ๐Ÿ’ง Light watering
Oct 4.3" 3" 1.3" ๐Ÿ’ง Light watering
Nov โ€” 2.7" 0" โ„๏ธ Dormant
Dec โ€” 2.4" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Wood County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Onion Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" โ€” every day above 50ยฐF deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Onion needs ~1,365 GDD — county provides 2,301 GDD Excellent fit

Onion Planting Timeline โ€” Wood County, OH

Onion Planting Calendar

Activity When Date Range
Start Indoors March 23 Mar 23 โ€“ Apr 6
Transplant Outdoors April 27 Apr 27 โ€“ May 11
Direct Sow April 13 Apr 13 โ€“ May 4
Harvest July 27 Jul 27 โ€“ Sep 14
Fall Sowing August 12 Aug 12 โ€“ Aug 26

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

90โ€“120 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 5b

๐Ÿ“† Growing Season

177 days in Wood County

Growing Tips for Onion in Wood County

Direct sow Onion outdoors after April 27 in Wood County when soil has warmed and frost danger has passed.

Common pests for Onion in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.

General growing tips

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 Wood County, OH?

Wood County is in Zone 5b with an average last frost of April 27. Plan your Onion planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Wood County, OH?

Wood County, Ohio is in USDA Hardiness Zone 5b. The average last spring frost is April 27 and first fall frost is October 21.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Wood County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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