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When to Plant Sunflower in Bosque 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.

Bosque County, Texas is in USDA Zone 8a. The average last spring frost is March 14 and the first fall frost is November 16, giving you a growing season of approximately 247 days.

At an elevation of 1,846 feet, Bosque County receives approximately 64.5 inches of rainfall annually with predominantly clay soil. Summer highs average 93ยฐF, providing good warmth for Sunflower during the growing season. Clay soil retains moisture well for Sunflower, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Sunflower root diseases.

Bosque County, TX (Zone 8a) Long season
247 days
Last Spring Frost March 14
247 growing days
First Fall Frost November 16

Bosque County Soil Profile

Soil Type

Clay

Soil pH

6.8-7.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (115 days to spare)
Start indoors: Jan 16 Transplant: Mar 20 🍅 Harvest: May 29 – Jul 17
Recommended (50%) ✓ Fits season (114 days to spare)
Start indoors: Jan 24 Transplant: Mar 28 🍅 Harvest: Jun 6 – Jul 25
Safe Start (90%) ✓ Fits season (104 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
Drought risk

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

Sunflower needs ~1,679 GDD — county provides 4,878 GDD Excellent fit

Sunflower Planting Timeline โ€” Bosque County, TX

Sunflower Planting Calendar

Activity When Date Range
Start Indoors January 24 Jan 24 โ€“ Feb 7
Transplant Outdoors March 28 Mar 28 โ€“ Apr 11
Direct Sow March 21 Mar 21 โ€“ Apr 11
Harvest June 6 Jun 6 โ€“ Jul 25

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

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Start Indoors
March Transplant Outdoors 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

247 days

Growing Tips for Bosque 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 Bosque County, TX?

Bosque County is in Zone 8a with an average last frost of March 14. Plan your Sunflower planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Bosque County, TX?

Bosque County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 14 and first fall frost is November 16.

๐ŸŒฑ

Plan Your Garden with Confidence

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