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When to Plant Sunflower in Jackson 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.

Jackson County, Texas is in USDA Zone 9a. The average last spring frost is February 21 and the first fall frost is December 5, giving you a growing season of approximately 287 days.

At an elevation of 286 feet, Jackson County receives approximately 64.3 inches of rainfall annually with predominantly loam soil. Summer highs average 103ยฐF, so Sunflower may need afternoon shade and extra watering during peak heat. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Sunflower root diseases.

Jackson County, TX (Zone 9a) Year-round
287 days
Last Spring Frost February 21
287 growing days
First Fall Frost December 5

Jackson County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (163 days to spare)
Start indoors: Dec 28 Transplant: Feb 15 🍅 Harvest: Apr 26 – Jun 14
Recommended (50%) ✓ Fits season (161 days to spare)
Start indoors: Jan 10 Transplant: Feb 28 🍅 Harvest: May 9 – Jun 27
Safe Start (90%) ✓ Fits season (153 days to spare)
Start indoors: Jan 31 Transplant: Mar 21 🍅 Harvest: May 30 – Jul 18

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
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Sunflower needs ~2,316 GDD — county provides 7,848 GDD Excellent fit

Sunflower Planting Timeline โ€” Jackson County, TX

Sunflower Planting Calendar

Activity When Date Range
Start Indoors January 10 Jan 10 โ€“ Jan 24
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 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 9a

Growing Season

287 days

Growing Tips for Jackson 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 Jackson County, TX?

Jackson County is in Zone 9a with an average last frost of February 21. Plan your Sunflower planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Jackson County, TX?

Jackson County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 21 and first fall frost is December 5.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Jackson County gardeners in Zone 9a 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 Jackson County, TX. Local conditions may vary. Last updated: April 2026.