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When to Plant Sunflower in Franklin County, TX

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.

Franklin County, Texas is in USDA Zone 8a. The average last spring frost is March 18 and the first fall frost is November 11, giving you a growing season of approximately 238 days.

At an elevation of 324 feet, Franklin County receives approximately 60 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 97ยฐF, so Sunflower may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring โ€” great for early planting โ€” but Sunflower will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Sunflower root diseases.

Franklin County, TX (Zone 8a) Long season
238 days
Last Spring Frost March 18
238 growing days
First Fall Frost November 11

Franklin County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.4-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (106 days to spare)
Start indoors: Jan 18 Transplant: Mar 22 🍅 Harvest: May 31 – Jul 19
Recommended (50%) ✓ Fits season (105 days to spare)
Start indoors: Jan 28 Transplant: Apr 1 🍅 Harvest: Jun 10 – Jul 29
Safe Start (90%) ✓ Fits season (100 days to spare)
Start indoors: Feb 18 Transplant: Apr 22 🍅 Harvest: Jul 1 – Aug 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
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Sunflower needs ~1,934 GDD — county provides 5,414 GDD Excellent fit

Sunflower Planting Timeline โ€” Franklin County, TX

Sunflower Planting Calendar

Activity When Date Range
Start Indoors January 28 Jan 28 โ€“ Feb 11
Transplant Outdoors April 1 Apr 1 โ€“ Apr 15
Direct Sow March 25 Mar 25 โ€“ Apr 15
Harvest June 10 Jun 10 โ€“ Jul 29

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

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Start Indoors
March Direct Sow
April Transplant Outdoors Direct Sow
May โ€”
June Harvest
July Harvest
August โ€”
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 8a

Growing Season

238 days

Growing Tips for Franklin 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 Franklin County, TX?

Franklin County is in Zone 8a with an average last frost of March 18. Plan your Sunflower planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Franklin County, TX?

Franklin County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 18 and first fall frost is November 11.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Franklin County gardeners in Zone 8a 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 Franklin County, TX. Local conditions may vary. Last updated: April 2026.