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When to Plant Sunflower in Grayson 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.

Grayson County, Texas is in USDA Zone 7b. The average last spring frost is March 14 and the first fall frost is November 18, giving you a growing season of approximately 249 days.

At an elevation of 248 feet, Grayson County receives approximately 71.2 inches of rainfall annually with predominantly loam soil. Summer highs average 88ยฐF, providing good warmth for Sunflower during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Sunflower root diseases.

Grayson County, TX (Zone 7b) Long season
249 days
Last Spring Frost March 14
249 growing days
First Fall Frost November 18

Grayson County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (116 days to spare)
Start indoors: Jan 16 Transplant: Mar 20 🍅 Harvest: May 29 – Jul 17
Recommended (50%) ✓ Fits season (116 days to spare)
Start indoors: Jan 24 Transplant: Mar 28 🍅 Harvest: Jun 6 – Jul 25
Safe Start (90%) ✓ Fits season (99 days to spare)
Start indoors: Feb 23 Transplant: Apr 27 🍅 Harvest: Jul 6 – Aug 24

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 ~1,360 GDD — county provides 3,984 GDD Excellent fit

Sunflower Planting Timeline โ€” Grayson 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 7b

Growing Season

249 days

Growing Tips for Grayson 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 Grayson County, TX?

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

Grayson County, Texas is in USDA Hardiness Zone 7b. The average last spring frost is March 14 and first fall frost is November 18.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Grayson County gardeners in Zone 7b 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 Grayson County, TX. Local conditions may vary. Last updated: April 2026.