When to Plant Onion in Culberson 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.
Culberson County, Texas is in USDA Zone 8a. The average last spring frost is March 29 and the first fall frost is November 11, giving you a growing season of approximately 227 days.
At an elevation of 2,716 feet, Culberson County receives approximately 50.5 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 96°F, so Onion may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Onion will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Onion root diseases.
Culberson County Soil Profile
Soil Type
Sandy Loam
Soil pH
7.5-8.1
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 | — | 3.5" | 0" | ❄️ Dormant |
| Feb | — | 3.2" | 0" | ❄️ Dormant |
| Mar | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| Apr | 4.3" | 1.8" | 2.5" | 🚿 Regular watering |
| May | 4.3" | 1.3" | 3" | 🚿 Regular watering |
| Jun | 4.3" | 1.7" | 2.6" | 🚿 Regular watering |
| Jul | 4.3" | 8.5" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 9.7" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 7.2" | 0" | ✅ Rainfall sufficient |
| Oct | 4.3" | 4.6" | 0" | ✅ Rainfall sufficient |
| Nov | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| Dec | — | 3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Culberson County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Onion Planting Timeline — Culberson County, TX
Onion Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 22 | Feb 22 – Mar 8 |
| Transplant Outdoors | March 29 | Mar 29 – Apr 12 |
| Direct Sow | March 15 | Mar 15 – Apr 5 |
| Harvest | June 28 | Jun 28 – Aug 16 |
| Fall Sowing | September 2 | Sep 2 – Sep 16 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors Transplant Outdoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | — |
| June | Harvest |
| July | Harvest |
| August | Harvest |
| September | Fall Sowing |
| October | — |
| 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 8a
📆 Growing Season
227 days in Culberson County
Growing Tips for Culberson 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 Culberson County, TX?
Culberson County is in Zone 8a with an average last frost of March 29. Plan your Onion planting based on this frost date — see the calendar above for exact timing.
What planting zone is Culberson County, TX?
Culberson County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 29 and first fall frost is November 11.
Your Culberson County Garden Planner — Free
A 22-page printable planner built for Culberson County (Zone 8a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.