When to Plant Sunflower in Denton 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.
Denton County, Texas is in USDA Zone 8a. The average last spring frost is March 10 and the first fall frost is November 20, giving you a growing season of approximately 255 days.
At an elevation of 1,848 feet, Denton County receives approximately 64.5 inches of rainfall annually with predominantly clay soil. Summer highs average 90°F, 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.
Denton County Soil Profile
Soil Type
Clay
Soil pH
6.7-8.1
Drainage
Well Drained
Plant Planting Risk Windows
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
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Sunflower Planting Timeline — Denton County, TX
Sunflower Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 20 | Jan 20 – Feb 3 |
| Transplant Outdoors | March 24 | Mar 24 – Apr 7 |
| Direct Sow | March 17 | Mar 17 – Apr 7 |
| Harvest | June 2 | Jun 2 – Jul 21 |
Plant 1" deep · 18" apart · Rows 30" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors |
| February | Start Indoors |
| March | Transplant Outdoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | — |
| June | Harvest |
| July | Harvest |
| August | — |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
Sun
Full Sun (6-8+ hours)
Water
Low — drought tolerant
Days to Maturity
70–100 days
Soil pH
6 – 7.5
USDA Zone
Zone 8a
Growing Season
255 days
Growing Tips for Denton 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
Level Up Your Garden
Sunflower in Other Locations
Frequently Asked Questions
When should I plant Sunflower in Denton County, TX?
Denton County is in Zone 8a with an average last frost of March 10. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.
What planting zone is Denton County, TX?
Denton County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 10 and first fall frost is November 20.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Denton County gardeners in Zone 8a organize planting dates, track what's growing, and never miss a planting window.
Get Your Free Garden Planner →Free download. Plan your entire garden season in minutes.