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When to Plant Sunflower in Falls 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.

Falls County, Texas is in USDA Zone 8a. The average last spring frost is March 17 and the first fall frost is November 13, giving you a growing season of approximately 241 days.

At an elevation of 66 feet, Falls County receives approximately 66.1 inches of rainfall annually with predominantly clay soil. Summer highs average 97ยฐF, so Sunflower may need afternoon shade and extra watering during peak heat. 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.

Falls County, TX (Zone 8a) Long season
241 days
Last Spring Frost March 17
241 growing days
First Fall Frost November 13

Falls County Soil Profile

Soil Type

Clay

Soil pH

7.1-8.2

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 (108 days to spare)
Start indoors: Jan 27 Transplant: Mar 31 🍅 Harvest: Jun 9 – Jul 28
Safe Start (90%) ✓ Fits season (101 days to spare)
Start indoors: Feb 18 Transplant: Apr 22 🍅 Harvest: Jul 1 – Aug 19

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 Falls County

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

Soil pH

Your soil pH (7.1โ€“8.2) is more alkaline than Sunflower prefers (6.0โ€“7.5). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.6%). 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 241-day season

Sow every 8 weeks. Last sowing by Aug 05 to harvest before frost.

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

Monthly Watering Guide for Sunflower

Sunflower needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Sunflower Needs Rainfall You Supplement Action
Jan โ€” 1.8" 0" โ„๏ธ Dormant
Feb โ€” 2" 0" โ„๏ธ Dormant
Mar 2.2" 4.7" 0" โœ… Rainfall sufficient
Apr 2.2" 6.7" 0" โœ… Rainfall sufficient
May 2.2" 10" 0" โœ… Rainfall sufficient
Jun 2.2" 9.5" 0" โœ… Rainfall sufficient
Jul 2.2" 9.2" 0" โœ… Rainfall sufficient
Aug 2.2" 7.4" 0" โœ… Rainfall sufficient
Sep 2.2" 7" 0" โœ… Rainfall sufficient
Oct 2.2" 4.1" 0" โœ… Rainfall sufficient
Nov 2.2" 2.2" 0" โœ… Rainfall sufficient
Dec โ€” 1.6" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Marโ€“Nov in Falls County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Sunflower Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" โ€” every day above 50ยฐF deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Sunflower needs ~1,934 GDD — county provides 5,482 GDD Excellent fit

Sunflower Planting Timeline โ€” Falls County, TX

Sunflower Planting Calendar

Activity When Date Range
Start Indoors January 27 Jan 27 โ€“ Feb 10
Transplant Outdoors March 31 Mar 31 โ€“ Apr 14
Direct Sow March 24 Mar 24 โ€“ Apr 14
Harvest June 9 Jun 9 โ€“ Jul 28

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

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 8a

๐Ÿ“† Growing Season

241 days in Falls County

Growing Tips for Sunflower in Falls County

Direct sow Sunflower outdoors after March 17 in Falls County when soil has warmed and frost danger has passed.

With Falls County's clay soil (36% clay), work in 3-4 inches of compost before planting Sunflower. Avoid tilling when soil is wet to prevent compaction.

With summer highs reaching 97ยฐF in Falls County, provide afternoon shade for Sunflower and water deeply in the morning.

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sunflower in Falls County, TX?

Falls County is in Zone 8a with an average last frost of March 17. Plan your Sunflower planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Falls County, TX?

Falls County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 17 and first fall frost is November 13.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Falls 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.

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