When to Plant Onion in McCulloch 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.
McCulloch County, Texas is in USDA Zone 8a. The average last spring frost is March 17 and the first fall frost is November 16, giving you a growing season of approximately 244 days.
At an elevation of 1,250 feet, McCulloch County receives approximately 60.1 inches of rainfall annually with predominantly loam soil. Summer highs average 96°F, so Onion may need afternoon shade and extra watering during peak heat. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Onion root diseases.
McCulloch County Soil Profile
Soil Type
Loam
Soil pH
6.8-7.7
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 McCulloch County
How your county's soil matches Onion's growing requirements.
Soil pH
Your soil pH (6.8–7.7) is more alkaline than Onion prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in McCulloch County is excellent for Onion — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is low (1.9%). Add 2-3 inches of compost before planting Onion.
How to Plant Onion
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
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 | — | 1.8" | 0" | ❄️ Dormant |
| Feb | — | 1.9" | 0" | ❄️ Dormant |
| Mar | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Apr | 4.3" | 6.6" | 0" | ✅ Rainfall sufficient |
| May | 4.3" | 9.8" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 8.6" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 8" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 7" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 5.1" | 0" | ✅ Rainfall sufficient |
| Oct | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| Nov | 4.3" | 2.2" | 2.1" | 💧 Light watering |
| Dec | — | 1.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in McCulloch County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Onion 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.
Onion Planting Timeline — McCulloch County, TX
Onion Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 10 | Feb 10 – Feb 24 |
| Transplant Outdoors | March 17 | Mar 17 – Mar 31 |
| Direct Sow | March 3 | Mar 3 – Mar 24 |
| Harvest | June 16 | Jun 16 – Aug 4 |
| Fall Sowing | September 7 | Sep 7 – Sep 21 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Transplant Outdoors Direct Sow |
| April | — |
| May | — |
| June | Harvest |
| July | Harvest |
| August | Harvest |
| September | Fall Sowing |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Natural rainfall sufficient
📅 Days to Maturity
90–120 days
🧪 Soil pH
Needs 6–7 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 8a
📆 Growing Season
244 days in McCulloch County
Growing Tips for Onion in McCulloch County
Direct sow Onion outdoors after March 17 in McCulloch County when soil has warmed and frost danger has passed.
With summer highs reaching 96°F in McCulloch County, provide afternoon shade for Onion and water deeply in the morning.
Common pests for Onion in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.
General growing tips
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
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Onion in Other Locations
Frequently Asked Questions
When should I plant Onion in McCulloch County, TX?
McCulloch County is in Zone 8a with an average last frost of March 17. Plan your Onion planting based on this frost date — see the calendar above for exact timing.
What planting zone is McCulloch County, TX?
McCulloch County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 17 and first fall frost is November 16.
Plan Your Garden with Confidence
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