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When to Plant Sunflower in Hardin 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.

Hardin County, Texas is in USDA Zone 8b. The average last spring frost is February 14 and the first fall frost is December 4, giving you a growing season of approximately 293 days.

At an elevation of 323 feet, Hardin County receives approximately 66.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 90ยฐF, providing good warmth for Sunflower during the growing season. 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.

Hardin County, TX (Zone 8b) Year-round
293 days
Last Spring Frost February 14
293 growing days
First Fall Frost December 4

Hardin County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.3-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (166 days to spare)
Start indoors: Dec 14 Transplant: Feb 15 🍅 Harvest: Apr 26 – Jun 14
Recommended (50%) ✓ Fits season (160 days to spare)
Start indoors: Dec 27 Transplant: Feb 28 🍅 Harvest: May 9 – Jun 27
Safe Start (90%) ✓ Fits season (155 days to spare)
Start indoors: Jan 16 Transplant: Mar 20 🍅 Harvest: May 29 – Jul 17

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
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Sunflower needs ~1,488 GDD — county provides 5,145 GDD Excellent fit

Sunflower Planting Timeline โ€” Hardin County, TX

Sunflower Planting Calendar

Activity When Date Range
Start Indoors December 27 Dec 27 โ€“ Jan 10
Transplant Outdoors February 28 Feb 28 โ€“ Mar 14
Direct Sow February 21 Feb 21 โ€“ Mar 14
Harvest May 9 May 9 โ€“ Jun 27

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

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Transplant Outdoors Direct Sow
March Transplant Outdoors Direct Sow
April โ€”
May Harvest
June Harvest
July โ€”
August โ€”
September โ€”
October โ€”
November โ€”
December Start Indoors

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 8b

Growing Season

293 days

Growing Tips for Hardin 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 Hardin County, TX?

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

What planting zone is Hardin County, TX?

Hardin County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is February 14 and first fall frost is December 4.

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Plan Your Garden with Confidence

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