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When to Plant Sunflower in Carter 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.

Carter County, Tennessee is in USDA Zone 6b. The average last spring frost is April 16 and the first fall frost is October 22, giving you a growing season of approximately 189 days.

At an elevation of 3,776 feet, Carter County receives approximately 53.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91ยฐF, providing good warmth for Sunflower during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Sunflower root diseases.

Carter County, TN (Zone 6b) Moderate season
189 days
Last Spring Frost April 16
189 growing days
First Fall Frost October 22

Carter County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (59 days to spare)
Start indoors: Feb 11 Transplant: Apr 22 🍅 Harvest: Jul 1 – Aug 19
Recommended (50%) ✓ Fits season (56 days to spare)
Start indoors: Feb 19 Transplant: Apr 30 🍅 Harvest: Jul 9 – Aug 27
Safe Start (90%) ✓ Fits season (53 days to spare)
Start indoors: Mar 7 Transplant: May 16 🍅 Harvest: Jul 25 – Sep 12

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
1.2″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Sunflower needs ~1,551 GDD — county provides 3,449 GDD Excellent fit

Sunflower Planting Timeline โ€” Carter County, TN

Sunflower Planting Calendar

Activity When Date Range
Start Indoors February 19 Feb 19 โ€“ Mar 5
Transplant Outdoors April 30 Apr 30 โ€“ May 14
Direct Sow April 23 Apr 23 โ€“ May 14
Harvest July 9 Jul 9 โ€“ Aug 27

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 โ€”
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 6b

Growing Season

189 days

Growing Tips for Carter 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 Carter County, TN?

Carter County is in Zone 6b with an average last frost of April 16. Plan your Sunflower planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Carter County, TN?

Carter County, Tennessee is in USDA Hardiness Zone 6b. The average last spring frost is April 16 and first fall frost is October 22.

๐ŸŒฑ

Plan Your Garden with Confidence

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