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When to Plant Onion in Cleveland County, OK

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.

Cleveland County, Oklahoma is in USDA Zone 7a. The average last spring frost is April 2 and the first fall frost is November 5, giving you a growing season of approximately 217 days.

At an elevation of 931 feet, Cleveland County receives approximately 26.4 inches of rainfall annually with predominantly loam soil. Summer highs average 94ยฐF, providing good warmth for Onion during the growing season.

Cleveland County, OK (Zone 7a) Long season
217 days
Last Spring Frost April 2
217 growing days
First Fall Frost November 5

Cleveland County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (82 days to spare)
Start indoors: Feb 14 Transplant: Mar 21 🍅 Harvest: Jun 20 – Aug 8
Recommended (50%) ✓ Fits season (77 days to spare)
Start indoors: Feb 26 Transplant: Apr 2 🍅 Harvest: Jul 2 – Aug 20
Safe Start (90%) ✓ Fits season (80 days to spare)
Start indoors: Mar 11 Transplant: Apr 15 🍅 Harvest: Jul 15 – Sep 2

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
0.5″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 1,133 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Onion needs ~2,152 GDD — county provides 4,448 GDD Excellent fit

Onion Planting Timeline โ€” Cleveland County, OK

Onion Planting Calendar

Activity When Date Range
Start Indoors February 26 Feb 26 โ€“ Mar 12
Transplant Outdoors April 2 Apr 2 โ€“ Apr 16
Direct Sow March 19 Mar 19 โ€“ Apr 9
Fall Sowing August 27 Aug 27 โ€“ Sep 10
Harvest July 2 Jul 2 โ€“ Aug 20

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

Month-by-Month Timeline

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

90โ€“120 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 7a

Growing Season

217 days

Growing Tips for Cleveland 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

Level Up Your Garden

Frequently Asked Questions

When should I plant Onion in Cleveland County, OK?

Cleveland County is in Zone 7a with an average last frost of April 2. Plan your Onion planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Cleveland County, OK?

Cleveland County, Oklahoma is in USDA Hardiness Zone 7a. The average last spring frost is April 2 and first fall frost is November 5.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Cleveland County gardeners in Zone 7a 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 Cleveland County, OK. Local conditions may vary. Last updated: April 2026.