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When to Plant Sunflower in Preble County, OH

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.

Preble County, Ohio is in USDA Zone 6a. The average last spring frost is April 24 and the first fall frost is October 21, giving you a growing season of approximately 180 days.

At an elevation of 1,250 feet, Preble County receives approximately 40 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91ยฐF, providing good warmth for Sunflower during the growing season.

Preble County, OH (Zone 6a) Moderate season
180 days
Last Spring Frost April 24
180 growing days
First Fall Frost October 21

Preble County Soil Profile

Soil Type

Silt Loam

Soil pH

6-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (48 days to spare)
Start indoors: Feb 18 Transplant: Apr 29 🍅 Harvest: Jul 8 – Aug 26
Recommended (50%) ✓ Fits season (47 days to spare)
Start indoors: Feb 27 Transplant: May 8 🍅 Harvest: Jul 17 – Sep 4
Safe Start (90%) ✓ Fits season (45 days to spare)
Start indoors: Mar 14 Transplant: May 23 🍅 Harvest: Aug 1 – Sep 19

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
0.9″/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 ~1,551 GDD — county provides 3,285 GDD Excellent fit

Sunflower Planting Timeline โ€” Preble County, OH

Sunflower Planting Calendar

Activity When Date Range
Start Indoors February 27 Feb 27 โ€“ Mar 13
Transplant Outdoors May 8 May 8 โ€“ May 22
Direct Sow May 1 May 1 โ€“ May 22
Harvest July 17 Jul 17 โ€“ Sep 4

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

Month-by-Month Timeline

MonthActivities
January โ€”
February Start Indoors
March Start Indoors
April โ€”
May Transplant Outdoors Direct Sow
June โ€”
July Harvest
August Harvest
September Harvest
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 6a

Growing Season

180 days

Growing Tips for Preble 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 Preble County, OH?

Preble County is in Zone 6a with an average last frost of April 24. Plan your Sunflower planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Preble County, OH?

Preble County, Ohio is in USDA Hardiness Zone 6a. The average last spring frost is April 24 and first fall frost is October 21.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Preble County gardeners in Zone 6a 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 Preble County, OH. Local conditions may vary. Last updated: April 2026.