Blog

When to Plant Sunflower in Parker 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.

Parker County, Texas is in USDA Zone 7b. The average last spring frost is March 18 and the first fall frost is November 12, giving you a growing season of approximately 239 days.

At an elevation of 4,469 feet, Parker County receives approximately 60.6 inches of rainfall annually with predominantly clay soil. Summer highs average 89ยฐF, 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.

Parker County, TX (Zone 7b) Long season
239 days
Last Spring Frost March 18
239 growing days
First Fall Frost November 12

Parker County Soil Profile

Soil Type

Clay

Soil pH

7.1-8.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (114 days to spare)
Start indoors: Jan 16 Transplant: Mar 20 🍅 Harvest: May 29 – Jul 17
Recommended (50%) ✓ Fits season (106 days to spare)
Start indoors: Jan 28 Transplant: Apr 1 🍅 Harvest: Jun 10 – Jul 29
Safe Start (90%) ✓ Fits season (103 days to spare)
Start indoors: Feb 22 Transplant: Apr 26 🍅 Harvest: Jul 5 – Aug 23

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.

Soil Compatibility in Parker County

How your county's soil matches Sunflower's growing requirements.

Soil pH

Your soil pH (7.1โ€“8.4) is more alkaline than Sunflower prefers (6.0โ€“7.5). Add sulfur or peat moss to lower pH.

Soil Texture

Your clay soil in Parker County is workable for Sunflower. Add compost annually to improve structure.

Organic Matter

Organic matter is moderate (3.2%). Annual compost additions will help Sunflower.

How to Plant Sunflower

1"
Planting Depth
18"
Between Plants
30"
Between Rows

Succession Planting Sunflower

4
successive plantings in your 239-day season

Sow every 8 weeks. Last sowing by Aug 04 to harvest before frost.

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 ~1,424 GDD — county provides 4,003 GDD Excellent fit

Sunflower Planting Timeline โ€” Parker 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

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.5"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

70โ€“100 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 7b

๐Ÿ“† Growing Season

239 days in Parker County

Growing Tips for Sunflower in Parker County

Direct sow Sunflower outdoors after March 18 in Parker County when soil has warmed and frost danger has passed.

With Parker County's clay soil (38% clay), work in 3-4 inches of compost before planting Sunflower. Avoid tilling when soil is wet to prevent compaction.

Common pests for Sunflower in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

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 Parker County, TX?

Parker County is in Zone 7b 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 Parker County, TX?

Parker County, Texas is in USDA Hardiness Zone 7b. The average last spring frost is March 18 and first fall frost is November 12.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Parker County gardeners in Zone 7b 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.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Parker County, TX. Local conditions may vary. Last updated: April 2026.