When to Plant Onion in San Augustine 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.
San Augustine County, Texas is in USDA Zone 9a. The average last spring frost is March 5 and the first fall frost is November 16, giving you a growing season of approximately 256 days.
At an elevation of 146 feet, San Augustine County receives approximately 62.7 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.
San Augustine County Soil Profile
Soil Type
Sandy Loam
Soil pH
5.4-6.6
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 | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.9" | 0" | ❄️ Dormant |
| Mar | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Apr | 4.3" | 6.2" | 0" | ✅ Rainfall sufficient |
| May | 4.3" | 8.2" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 10.7" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 8.7" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 8.2" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 5.8" | 0" | ✅ Rainfall sufficient |
| Oct | 4.3" | 4.2" | 0.1" | 💧 Light watering |
| Nov | 4.3" | 2.3" | 2" | 💧 Light watering |
| Dec | — | 1.5" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in San Augustine County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Onion Planting Timeline — San Augustine County, TX
Onion Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 5 | Feb 5 – Feb 19 |
| Transplant Outdoors | March 5 | Mar 5 – Mar 19 |
| Direct Sow | February 12 | Feb 12 – Mar 5 |
| Harvest | June 4 | Jun 4 – Jul 23 |
| Fall Sowing | September 21 | Sep 21 – Oct 5 |
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
256 days in San Augustine County
Growing Tips for San Augustine 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 San Augustine County, TX?
San Augustine County is in Zone 9a with an average last frost of March 5. Plan your Onion planting based on this frost date — see the calendar above for exact timing.
What planting zone is San Augustine County, TX?
San Augustine County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is March 5 and first fall frost is November 16.
Your San Augustine County Garden Planner — Free
A 22-page printable planner built for San Augustine 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.