When to Plant Onion in Brazos County, TX
Onions are a fundamental kitchen staple available in yellow, white, and red varieties. Choose long-day, short-day, or intermediate types based on your latitude.
Brazos County, Texas is in USDA Zone 9a. The average last spring frost is March 4 and the first fall frost is November 25, giving you a growing season of approximately 266 days.
At an elevation of 74 feet, Brazos County receives approximately 63.5 inches of rainfall annually with predominantly clay soil. Summer highs average 91°F, providing good warmth for Onion during the growing season. Clay soil retains moisture well for Onion, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Onion root diseases.
Brazos County Soil Profile
Soil Type
Clay
Soil pH
6.7-7.8
Drainage
Well Drained
Monthly Watering Guide for Onion
Onion needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Onion Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.4" | 0" | ❄️ Dormant |
| Feb | — | 2.2" | 0" | ❄️ Dormant |
| Mar | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| Apr | 4.3" | 7.4" | 0" | ✅ Rainfall sufficient |
| May | 4.3" | 8.5" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 10.4" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 8.9" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 7.7" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 5.5" | 0" | ✅ Rainfall sufficient |
| Oct | 4.3" | 4" | 0.3" | 💧 Light watering |
| Nov | 4.3" | 2.2" | 2.1" | 💧 Light watering |
| Dec | — | 1.4" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Brazos County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Onion Planting Timeline — Brazos County, TX
Onion Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 4 | Feb 4 – Feb 18 |
| Transplant Outdoors | March 4 | Mar 4 – Mar 18 |
| Direct Sow | February 11 | Feb 11 – Mar 4 |
| Harvest | June 3 | Jun 3 – Jul 22 |
| Fall Sowing | September 30 | Sep 30 – Oct 14 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors Direct Sow |
| March | Transplant Outdoors Direct Sow |
| April | — |
| May | — |
| June | Harvest |
| July | Harvest |
| August | — |
| September | Fall Sowing |
| October | Fall Sowing |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Moderate — regular watering
📅 Days to Maturity
90–120 days
🧪 Soil pH
Needs 6–7 · Your soil: N/A
🗺️ USDA Zone
Zone 9a
📆 Growing Season
266 days in Brazos County
Growing Tips for Brazos County
Start seeds indoors 8-10 weeks before transplanting. Match day-length type to your latitude. Stop watering when tops begin to fall over and cure bulbs for 2-3 weeks before storage.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Onion in Other Locations
Frequently Asked Questions
When should I plant Onion in Brazos County, TX?
Brazos County is in Zone 9a with an average last frost of March 4. Plan your Onion planting based on this frost date — see the calendar above for exact timing.
What planting zone is Brazos County, TX?
Brazos County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is March 4 and first fall frost is November 25.
Your Brazos County Garden Planner — Free
A 22-page printable planner built for Brazos 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.