When to Plant Sunflower in Hidalgo County, TX
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.
Hidalgo County, Texas is in USDA Zone 10a. The average last spring frost is February 6 and the first fall frost is December 18, giving you a growing season of approximately 315 days.
At an elevation of 4,081 feet, Hidalgo County receives approximately 67 inches of rainfall annually with predominantly loam soil. Summer highs average 100°F, so Sunflower may need afternoon shade and extra watering during peak heat. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Sunflower root diseases.
Hidalgo County Soil Profile
Soil Type
Loam
Soil pH
6.2-7.8
Drainage
Well Drained
Monthly Watering Guide for Sunflower
Sunflower needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Sunflower Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.4" | 0" | ❄️ Dormant |
| Feb | 4.3" | 2.1" | 2.2" | 🚿 Regular watering |
| Mar | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Apr | 4.3" | 6.7" | 0" | ✅ Rainfall sufficient |
| May | 4.3" | 10.1" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 9.4" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 9.3" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 8.7" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 6.9" | 0" | ✅ Rainfall sufficient |
| Oct | 4.3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Nov | 4.3" | 2.5" | 1.8" | 💧 Light watering |
| Dec | 4.3" | 1.8" | 2.5" | 🚿 Regular watering |
Water needs are for active growing months only (Feb–Dec in Hidalgo County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Sunflower Planting Timeline — Hidalgo County, TX
Sunflower Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 16 | Jan 16 – Jan 30 |
| Transplant Outdoors | December 26 | Dec 26 – Jan 9 |
| Direct Sow | December 26 | Dec 26 – Jan 16 |
| Bloom | March 20 | Mar 20 – Sep 18 |
Plant 1" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors Transplant Outdoors Direct Sow |
| February | — |
| March | Bloom |
| April | Bloom |
| May | Bloom |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | — |
| November | — |
| December | Transplant Outdoors Direct Sow |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Low — drought tolerant
📅 Days to Maturity
70–100 days
🧪 Soil pH
Needs 6–7.5 · Your soil: N/A
🗺️ USDA Zone
Zone 10a
📆 Growing Season
315 days in Hidalgo County
Growing Tips for Hidalgo County
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
Check more plant combinations with our Companion Planting Checker →
Sunflower in Other Locations
Frequently Asked Questions
When should I plant Sunflower in Hidalgo County, TX?
Hidalgo County is in Zone 10a with an average last frost of February 6. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.
What planting zone is Hidalgo County, TX?
Hidalgo County, Texas is in USDA Hardiness Zone 10a. The average last spring frost is February 6 and first fall frost is December 18.
Your Hidalgo County Garden Planner — Free
A 22-page printable planner built for Hidalgo County (Zone 10a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.