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When to Plant Sunflower in Leon 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.

Leon County, Texas is in USDA Zone 8a. The average last spring frost is March 9 and the first fall frost is November 14, giving you a growing season of approximately 250 days.

At an elevation of 226 feet, Leon County receives approximately 72.8 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 91ยฐF, 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.

Leon County, TX (Zone 8a) Long season
250 days
Last Spring Frost March 9
250 growing days
First Fall Frost November 14

Leon County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.4-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (118 days to spare)
Start indoors: Jan 13 Transplant: Mar 17 🍅 Harvest: May 26 – Jul 14
Recommended (50%) ✓ Fits season (117 days to spare)
Start indoors: Jan 19 Transplant: Mar 23 🍅 Harvest: Jun 1 – Jul 20
Safe Start (90%) ✓ Fits season (107 days to spare)
Start indoors: Feb 17 Transplant: Apr 21 🍅 Harvest: Jun 30 – Aug 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.

Soil Compatibility in Leon County

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

Soil pH

Your soil pH (5.4โ€“6.2) is more acidic than Sunflower prefers (6.0โ€“7.5). Add garden lime to raise pH.

Soil Texture

Sandy soil in Leon 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 (1.9%). 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

4
successive plantings in your 250-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
1.2″/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€” 1.7" 0" โ„๏ธ Dormant
Feb โ€” 2.5" 0" โ„๏ธ Dormant
Mar 2.2" 4.6" 0" โœ… Rainfall sufficient
Apr 2.2" 7" 0" โœ… Rainfall sufficient
May 2.2" 11.4" 0" โœ… Rainfall sufficient
Jun 2.2" 11.2" 0" โœ… Rainfall sufficient
Jul 2.2" 8.7" 0" โœ… Rainfall sufficient
Aug 2.2" 9.6" 0" โœ… Rainfall sufficient
Sep 2.2" 7.3" 0" โœ… Rainfall sufficient
Oct 2.2" 4.3" 0" โœ… Rainfall sufficient
Nov 2.2" 2.7" 0" โœ… Rainfall sufficient
Dec โ€” 1.8" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Marโ€“Nov in Leon 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 ~1,551 GDD — county provides 4,562 GDD Excellent fit

Sunflower Planting Timeline โ€” Leon County, TX

Sunflower Planting Calendar

Activity When Date Range
Start Indoors January 19 Jan 19 โ€“ Feb 2
Transplant Outdoors March 23 Mar 23 โ€“ Apr 6
Direct Sow March 16 Mar 16 โ€“ Apr 6
Harvest June 1 Jun 1 โ€“ Jul 20

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_acidic

๐Ÿ—บ๏ธ USDA Zone

Zone 8a

๐Ÿ“† Growing Season

250 days in Leon County

Growing Tips for Sunflower in Leon County

Direct sow Sunflower outdoors after March 09 in Leon County when soil has warmed and frost danger has passed.

Sandy soil in Leon 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.

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 Leon County, TX?

Leon County is in Zone 8a with an average last frost of March 9. Plan your Sunflower planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Leon County, TX?

Leon County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 9 and first fall frost is November 14.

๐ŸŒฑ

Plan Your Garden with Confidence

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