Blog

When to Plant Sunflower in Cleveland County, OK

Sunflowers are tall, cheerful annuals grown for their edible seeds and as pollinator magnets. They come in sizes from 2-foot dwarfs to 12-foot giants.

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 Sunflower 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 (89 days to spare)
Start indoors: Jan 31 Transplant: Apr 4 🍅 Harvest: Jun 13 – Aug 1
Recommended (50%) ✓ Fits season (84 days to spare)
Start indoors: Feb 12 Transplant: Apr 16 🍅 Harvest: Jun 25 – Aug 13
Safe Start (90%) ✓ Fits season (87 days to spare)
Start indoors: Feb 25 Transplant: Apr 29 🍅 Harvest: Jul 8 – Aug 26

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
0.5″/week
Rainfall provides
0.5″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

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

Sunflower needs ~1,742 GDD — county provides 4,448 GDD Excellent fit

Sunflower Planting Timeline โ€” Cleveland County, OK

Sunflower Planting Calendar

Activity When Date Range
Start Indoors February 12 Feb 12 โ€“ Feb 26
Transplant Outdoors April 16 Apr 16 โ€“ Apr 30
Direct Sow April 9 Apr 9 โ€“ Apr 30
Harvest June 25 Jun 25 โ€“ Aug 13

Plant 1" deep ยท 18" apart ยท Rows 30" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Low โ€” drought tolerant

Days to Maturity

70โ€“100 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 7a

Growing Season

217 days

Growing Tips for Cleveland County

Direct sow after last frost. Stake tall varieties in windy areas. Harvest seed heads when the back turns brown and seeds are plump. Dry heads upside down.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Level Up Your Garden

Frequently Asked Questions

When should I plant Sunflower in Cleveland County, OK?

Cleveland County is in Zone 7a with an average last frost of April 2. Plan your Sunflower 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.

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 Cleveland County, OK. Local conditions may vary. Last updated: April 2026.