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When to Plant Sunflower in Stonewall 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.

Stonewall County, Texas is in USDA Zone 7b. The average last spring frost is March 24 and the first fall frost is November 14, giving you a growing season of approximately 235 days.

At an elevation of 2,417 feet, Stonewall County receives approximately 57.8 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 98ยฐF, so Sunflower may need afternoon shade and extra watering during peak heat. 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.

Stonewall County, TX (Zone 7b) Long season
235 days
Last Spring Frost March 24
235 growing days
First Fall Frost November 14

Stonewall County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.2-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (99 days to spare)
Start indoors: Jan 27 Transplant: Mar 31 🍅 Harvest: Jun 9 – Jul 28
Recommended (50%) ✓ Fits season (102 days to spare)
Start indoors: Feb 3 Transplant: Apr 7 🍅 Harvest: Jun 16 – Aug 4
Safe Start (90%) ✓ Fits season (92 days to spare)
Start indoors: Feb 25 Transplant: Apr 29 🍅 Harvest: Jul 8 – Aug 26

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 Stonewall County

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

Soil pH

Your soil pH (7.2โ€“8.2) is more alkaline than Sunflower prefers (6.0โ€“7.5). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Stonewall County warms quickly in spring but drains fast. Sunflower will need more frequent watering and regular compost additions to retain nutrients.

Organic Matter

Organic matter is low (0.9%). Add 2-3 inches of compost before planting Sunflower.

How to Plant Sunflower

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

Succession Planting Sunflower

3
successive plantings in your 235-day season

Sow every 8 weeks. Last sowing by Aug 06 to harvest before frost.

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
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

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€” 3.4" 0" โ„๏ธ Dormant
Feb โ€” 3.2" 0" โ„๏ธ Dormant
Mar 2.2" 3.4" 0" โœ… Rainfall sufficient
Apr 2.2" 2.1" 0.1" ๐Ÿ’ง Light watering
May 2.2" 1.3" 0.9" ๐Ÿ’ง Light watering
Jun 2.2" 2.3" 0" โœ… Rainfall sufficient
Jul 2.2" 10" 0" โœ… Rainfall sufficient
Aug 2.2" 12.4" 0" โœ… Rainfall sufficient
Sep 2.2" 7.7" 0" โœ… Rainfall sufficient
Oct 2.2" 4.6" 0" โœ… Rainfall sufficient
Nov 2.2" 3.4" 0" โœ… Rainfall sufficient
Dec โ€” 4.1" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Marโ€“Nov in Stonewall 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 ~1,998 GDD — county provides 5,522 GDD Excellent fit

Sunflower Planting Timeline โ€” Stonewall County, TX

Sunflower Planting Calendar

Activity When Date Range
Start Indoors February 3 Feb 3 โ€“ Feb 17
Transplant Outdoors April 7 Apr 7 โ€“ Apr 21
Direct Sow March 31 Mar 31 โ€“ Apr 21
Harvest June 16 Jun 16 โ€“ Aug 4

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

Month-by-Month Timeline

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

235 days in Stonewall County

Growing Tips for Sunflower in Stonewall County

Direct sow Sunflower outdoors after March 24 in Stonewall County when soil has warmed and frost danger has passed.

Sandy soil in Stonewall County dries quickly โ€” mulch Sunflower with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 98ยฐF in Stonewall 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 Stonewall County, TX?

Stonewall County is in Zone 7b with an average last frost of March 24. Plan your Sunflower planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Stonewall County, TX?

Stonewall County, Texas is in USDA Hardiness Zone 7b. The average last spring frost is March 24 and first fall frost is November 14.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Stonewall 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 Stonewall County, TX. Local conditions may vary. Last updated: April 2026.