When to Plant Sunflower in Hays 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.
Hays County, Texas is in USDA Zone 8b. The average last spring frost is March 6 and the first fall frost is November 22, giving you a growing season of approximately 261 days.
At an elevation of 3,119 feet, Hays County receives approximately 61.8 inches of rainfall annually with predominantly clay soil. Summer highs average 90°F, providing good warmth for Sunflower during the growing season. 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.
Hays County Soil Profile
Soil Type
Clay
Soil pH
7-8
Drainage
Well Drained
Plant Planting Risk Windows
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 Hays County
How your county's soil matches Sunflower's growing requirements.
Soil pH
Your soil pH (7.0–8.0) overlaps with Sunflower's range (6.0–7.5), though not a perfect match.
Soil Texture
Heavy clay soil (45% clay) in Hays County compacts easily and drains slowly. Amend with compost and avoid working soil when wet.
Organic Matter
Organic matter is moderate (2.8%). Annual compost additions will help Sunflower.
How to Plant Sunflower
Succession Planting Sunflower
Sow every 8 weeks. Last sowing by Aug 14 to harvest before frost.
Plant Water Budget
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 | — | 1.6" | 0" | ❄️ Dormant |
| Feb | — | 2.3" | 0" | ❄️ Dormant |
| Mar | 2.2" | 3.5" | 0" | ✅ Rainfall sufficient |
| Apr | 2.2" | 6.5" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 9.5" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 9.8" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 7" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 8.1" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 5.1" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 4.2" | 0" | ✅ Rainfall sufficient |
| Nov | 2.2" | 2.3" | 0" | ✅ Rainfall sufficient |
| Dec | — | 1.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Hays 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 Planting Timeline — Hays County, TX
Sunflower Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 16 | Jan 16 – Jan 30 |
| Transplant Outdoors | March 20 | Mar 20 – Apr 3 |
| Direct Sow | March 13 | Mar 13 – Apr 3 |
| Harvest | May 29 | May 29 – Jul 17 |
Plant 1" deep · 18" apart · Rows 30" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors |
| February | — |
| March | Transplant Outdoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | Harvest |
| June | Harvest |
| July | Harvest |
| August | — |
| September | — |
| 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: acceptable
🗺️ USDA Zone
Zone 8b
📆 Growing Season
261 days in Hays County
Growing Tips for Sunflower in Hays County
Direct sow Sunflower outdoors after March 06 in Hays County when soil has warmed and frost danger has passed.
With Hays County's clay soil (45% clay), work in 3-4 inches of compost before planting Sunflower. Avoid tilling when soil is wet to prevent compaction.
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
Check more plant combinations with our Companion Planting Checker →
Sunflower in Other Locations
Frequently Asked Questions
When should I plant Sunflower in Hays County, TX?
Hays County is in Zone 8b with an average last frost of March 6. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.
What planting zone is Hays County, TX?
Hays County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is March 6 and first fall frost is November 22.
Plan Your Garden with Confidence
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