When to Plant Onion in Hill County, TX
Your June planting checklist for Hill County, Texas
We've pulled the most time-sensitive tasks for Hill County, Texas this June and put them front and centre. Tackle them in order.
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Harvest onion as they ripen
Check every 1–2 days. Many of these get tough or go to seed if you wait too long.
July will be here before you know it — start on
- First harvests: onion
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.
Hill County, Texas is in USDA Zone 8b. The average last spring frost is March 12 and the first fall frost is November 19, giving you a growing season of approximately 252 days.
At an elevation of 2,597 feet, Hill County receives approximately 54.7 inches of rainfall annually with predominantly clay soil. Summer highs average 93°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.
Hill County Soil Profile
Soil Type
Clay
Soil pH
7.3-7.7
Drainage
Well Drained
Onion 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 Hill County
How your county's soil matches Onion's growing requirements.
Soil pH
Your soil pH (7.3–7.7) is more alkaline than Onion prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
Your clay soil in Hill County is workable for Onion. Add compost annually to improve structure.
Organic Matter
Organic matter is moderate (2.9%). Annual compost additions will help Onion.
How to Plant Onion
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Onion 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 | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.5" | 0" | ❄️ Dormant |
| Mar | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Apr | 4.3" | 5.9" | 0" | ✅ Rainfall sufficient |
| May | 4.3" | 6.7" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 9.7" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 7.3" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 7" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 4.8" | 0" | ✅ Rainfall sufficient |
| Oct | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Nov | 4.3" | 2" | 2.3" | 🚿 Regular watering |
| Dec | — | 1.4" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Hill 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 — Hill County, TX
Onion Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 5 | Feb 5 – Feb 19 |
| Transplant Outdoors | March 12 | Mar 12 – Mar 26 |
| Direct Sow | February 26 | Feb 26 – Mar 19 |
| Harvest | June 11 | Jun 11 – Jul 30 |
| Fall Sowing | September 10 | Sep 10 – Sep 24 |
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 | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Only during dry spells
📅 Days to Maturity
90–120 days
🧪 Soil pH
Needs 6–7 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 8b
📆 Growing Season
252 days in Hill County
Growing Tips for Onion in Hill County
Direct sow Onion outdoors after March 12 in Hill County when soil has warmed and frost danger has passed.
With Hill County's clay soil (36% clay), work in 3-4 inches of compost before planting Onion. Avoid tilling when soil is wet to prevent compaction.
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
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 Hill County, TX?
Hill County is in Zone 8b with an average last frost of March 12. Plan your Onion planting based on this frost date — see the calendar above for exact timing.
What planting zone is Hill County, TX?
Hill County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is March 12 and first fall frost is November 19.
Your Hill County Garden Planner — Free
A 22-page printable planner built for Hill County (Zone 8b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.