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When to Plant Sunflower in Henry County, TN

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.

Henry County, Tennessee is in USDA Zone 7a. The average last spring frost is April 6 and the first fall frost is October 28, giving you a growing season of approximately 205 days.

At an elevation of 1,382 feet, Henry County receives approximately 40.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90ยฐF, providing good warmth for Sunflower during the growing season.

Henry County, TN (Zone 7a) Long season
205 days
Last Spring Frost April 6
205 growing days
First Fall Frost October 28

Henry County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (72 days to spare)
Start indoors: Feb 9 Transplant: Apr 13 🍅 Harvest: Jun 22 – Aug 10
Recommended (50%) ✓ Fits season (72 days to spare)
Start indoors: Feb 16 Transplant: Apr 20 🍅 Harvest: Jun 29 – Aug 17
Safe Start (90%) ✓ Fits season (75 days to spare)
Start indoors: Mar 1 Transplant: May 3 🍅 Harvest: Jul 12 – Aug 30

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
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Sunflower needs ~1,488 GDD — county provides 3,587 GDD Excellent fit

Sunflower Planting Timeline โ€” Henry County, TN

Sunflower Planting Calendar

Activity When Date Range
Start Indoors February 16 Feb 16 โ€“ Mar 2
Transplant Outdoors April 20 Apr 20 โ€“ May 4
Direct Sow April 13 Apr 13 โ€“ May 4
Harvest June 29 Jun 29 โ€“ Aug 17

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

Month-by-Month Timeline

MonthActivities
January โ€”
February Start Indoors
March Start Indoors
April Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
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

205 days

Growing Tips for Henry 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 Henry County, TN?

Henry County is in Zone 7a with an average last frost of April 6. Plan your Sunflower planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Henry County, TN?

Henry County, Tennessee is in USDA Hardiness Zone 7a. The average last spring frost is April 6 and first fall frost is October 28.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Henry 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 Henry County, TN. Local conditions may vary. Last updated: April 2026.