When to Plant Sunflower in Colorado County, TX
May in Colorado County, Texas — your action list
Each item below is timed to Colorado County, Texas's frost dates and soil temperatures. Skip nothing, stress about nothing.
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Collect sunflower at their peak
This is the payoff month. Bring a basket, bring a friend, and get into the beds.
Get ahead of June
- First harvests: sunflower
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.
Colorado County, Texas is in USDA Zone 9a. The average last spring frost is February 26 and the first fall frost is December 4, giving you a growing season of approximately 281 days.
At an elevation of 87 feet, Colorado County receives approximately 70.5 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.
Colorado County Soil Profile
Soil Type
Clay
Soil pH
7.3-7.8
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 Colorado County
How your county's soil matches Sunflower's growing requirements.
Soil pH
Your soil pH (7.3–7.8) is more alkaline than Sunflower prefers (6.0–7.5). Add sulfur or peat moss to lower pH.
Soil Texture
Heavy clay soil (42% clay) in Colorado County compacts easily and drains slowly. Amend with compost and avoid working soil when wet.
Drainage
Sunflower prefers dry conditions but your soil drains poorly. Use raised beds or mounded rows to prevent root rot.
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 26 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 | — | 1.9" | 0" | ❄️ Dormant |
| Feb | 2.2" | 2.3" | 0" | ✅ Rainfall sufficient |
| Mar | 2.2" | 4.5" | 0" | ✅ Rainfall sufficient |
| Apr | 2.2" | 8" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 10.9" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 10.3" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 9.3" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 8.7" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 5.5" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 4.8" | 0" | ✅ Rainfall sufficient |
| Nov | 2.2" | 2.3" | 0" | ✅ Rainfall sufficient |
| Dec | 2.2" | 1.9" | 0.3" | 💧 Light watering |
Water needs are for active growing months only (Feb–Dec in Colorado 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 — Colorado County, TX
Sunflower Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 15 | Jan 15 – Jan 29 |
| Transplant Outdoors | March 5 | Mar 5 – Mar 19 |
| Direct Sow | February 26 | Feb 26 – Mar 19 |
| Harvest | May 14 | May 14 – Jul 2 |
Plant 1" deep · 18" apart · Rows 30" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors |
| February | Direct Sow |
| March | Transplant Outdoors Direct Sow |
| April | — |
| 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: too_alkaline
🗺️ USDA Zone
Zone 9a
📆 Growing Season
281 days in Colorado County
Growing Tips for Sunflower in Colorado County
Direct sow Sunflower outdoors after February 26 in Colorado County when soil has warmed and frost danger has passed.
With Colorado County's clay soil (42% 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 Colorado County, TX?
Colorado County is in Zone 9a with an average last frost of February 26. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.
What planting zone is Colorado County, TX?
Colorado County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 26 and first fall frost is December 4.
Your Colorado County Garden Planner — Free
A 24-page printable planner built for Colorado 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.