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When to Plant Sunflower in Waller County, TX

Waller County, Texas Zone 9a June

June in Waller County, Texas — your action list

Your Waller County, Texas garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost February 19
Avg. first frost December 4
Soil temp (4") 81°F
Watering Low
Pest pressure High
Daylight 13.9 hrs
  1. Basket week: sunflower

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

A few tasks this June that'll pay off in July
  • First harvests: sunflower

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Sunflower (Helianthus annuus) is a fast-growing North American native annual famous for its towering stems and brilliant yellow heads. It thrives in full sun and heat, producing large, pollen-rich blooms that attract bees, butterflies, and seed-eating birds. Varieties range from 18-inch dwarfs to 12-foot giants and nearly every color except blue.

Waller County, Texas is in USDA Zone 9a. The average last spring frost is February 19 and the first fall frost is December 4, giving you a growing season of approximately 288 days.

At an elevation of 376 feet, Waller County receives approximately 64.1 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 95°F, so Sunflower may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — 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.

Annual Blooms in Summer Pollinator-friendly Good for cutting
Waller County, TX (Zone 9a) Year-round
288 days
Last Spring Frost February 19
288 growing days
First Fall Frost December 4

Waller County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.6-6.2

Drainage

Well Drained

Sunflower Planting Risk Windows

Early Start (70% safe) ✓ Fits season (69 days to spare)
Start indoors: Jan 21 Transplant: Jan 21 🌸 Bloom: Apr 15 – Sep 16
Recommended (50%) ✓ Fits season (71 days to spare)
Start indoors: Jan 29 Transplant: Jan 29 🌸 Bloom: Apr 23 – Sep 24
Safe Start (90%) ✓ Fits season (70 days to spare)
Start indoors: Feb 16 Transplant: Feb 16 🌸 Bloom: May 11 – Oct 12

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 Waller County

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

Soil pH

Your soil pH (5.6–6.2) is more acidic than Sunflower prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

Sandy soil in Waller 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 moderate (2.0%). Annual compost additions will help Sunflower.

How to Plant Sunflower

1"
Planting Depth
18"
Between Plants
24"
Between Rows

Succession Planting Sunflower

4
successive plantings in your 288-day season

Sow every 8 weeks. Last sowing by Aug 26 to harvest before frost.

Sunflower Water Budget

Plant needs
0.5″/week
Rainfall provides
0.9″/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 1.7" 0" ❄️ Dormant
Feb 2.2" 2.4" 0" ✅ Rainfall sufficient
Mar 2.2" 4.6" 0" ✅ Rainfall sufficient
Apr 2.2" 7.3" 0" ✅ Rainfall sufficient
May 2.2" 8.9" 0" ✅ Rainfall sufficient
Jun 2.2" 9.1" 0" ✅ Rainfall sufficient
Jul 2.2" 7.9" 0" ✅ Rainfall sufficient
Aug 2.2" 7" 0" ✅ Rainfall sufficient
Sep 2.2" 6.9" 0" ✅ Rainfall sufficient
Oct 2.2" 4.3" 0" ✅ Rainfall sufficient
Nov 2.2" 2.2" 0" ✅ Rainfall sufficient
Dec 2.2" 1.7" 0.5" 💧 Light watering

Water needs are for active growing months only (Feb–Dec in Waller County). Supplement amounts are based on average rainfall — 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" — every day above 50°F 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 ~1,806 GDD — county provides 6,141 GDD Excellent fit

Sunflower Planting Timeline — Waller County, TX

Sunflower Planting Calendar

Activity When Date Range
Start Indoors January 29 Jan 29 – Feb 12
Transplant Outdoors January 29 Jan 29 – Feb 12
Direct Sow January 29 Jan 29 – Feb 19
Bloom April 23 Apr 23 – Sep 24

Plant 1" deep · 18" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January Start Indoors Transplant Outdoors Direct Sow
February Start Indoors Transplant Outdoors Direct Sow
March
April Bloom
May Bloom
June Bloom
July Bloom
August Bloom
September Bloom
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 9a

📆 Growing Season

288 days in Waller County

Growing Tips for Sunflower in Waller County

Direct sow Sunflower outdoors after February 19 in Waller County when soil has warmed and frost danger has passed.

Sandy soil in Waller County dries quickly — 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 1 inch deep after last frost; germination takes 7-14 days at 65-75°F soil. Sunflowers dislike root disturbance so direct sowing is strongly preferred over transplanting. Plant in succession every 2 weeks for extended bloom. Stake tall varieties. Avoid overwatering — they tolerate drought once established. Birds will self-deadhead seed heads; leave them up through fall for wildlife.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes
  • Pole_beans

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sunflower in Waller County, TX?

Waller County is in Zone 9a with an average last frost of February 19. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Waller County, TX?

Waller County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 19 and first fall frost is December 4.

🌱

Your Waller County Garden Planner — Free

A 22-page printable planner built for Waller County (Zone 9a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Waller County, TX. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.