When to Plant Onion in Bastrop County, TX
Your May planting checklist for Bastrop County, Texas
Your garden in Bastrop County, Texas is working on a schedule, even when you're not. Here's where you should be this May.
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Harvest onion as they ripen
The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.
Coming up in June — start thinking about
- 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.
Bastrop County, Texas is in USDA Zone 9a. The average last spring frost is February 27 and the first fall frost is December 1, giving you a growing season of approximately 277 days.
At an elevation of 3,716 feet, Bastrop County receives approximately 57 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.
Bastrop County Soil Profile
Soil Type
Clay
Soil pH
7.2-7.9
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 Bastrop County
How your county's soil matches Onion's growing requirements.
Soil pH
Your soil pH (7.2–7.9) is more alkaline than Onion prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
Heavy clay soil (47% clay) in Bastrop County compacts easily and drains slowly. Amend with compost and avoid working soil when wet.
Organic Matter
Organic matter is moderate (3.0%). Annual compost additions will help Onion.
How to Plant Onion
Fall planting: Sow 8 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 | — | 1.5" | 0" | ❄️ Dormant |
| Feb | 4.3" | 2.1" | 2.2" | 🚿 Regular watering |
| Mar | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Apr | 4.3" | 6.1" | 0" | ✅ Rainfall sufficient |
| May | 4.3" | 8.8" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 9.4" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 6.7" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 5.8" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 5.6" | 0" | ✅ Rainfall sufficient |
| Oct | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Nov | 4.3" | 1.9" | 2.4" | 🚿 Regular watering |
| Dec | 4.3" | 1.5" | 2.8" | 🚿 Regular watering |
Water needs are for active growing months only (Feb–Dec in Bastrop 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 — Bastrop County, TX
Onion Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 30 | Jan 30 – Feb 13 |
| Transplant Outdoors | February 27 | Feb 27 – Mar 13 |
| Direct Sow | February 6 | Feb 6 – Feb 27 |
| Harvest | May 29 | May 29 – Jul 17 |
| Fall Sowing | October 6 | Oct 6 – Oct 20 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors |
| February | Start Indoors Transplant Outdoors Direct Sow |
| March | Transplant Outdoors |
| April | — |
| May | Harvest |
| June | Harvest |
| July | Harvest |
| August | — |
| September | — |
| October | Fall Sowing |
| 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 9a
📆 Growing Season
277 days in Bastrop County
Growing Tips for Onion in Bastrop County
Direct sow Onion outdoors after February 27 in Bastrop County when soil has warmed and frost danger has passed.
With Bastrop County's clay soil (47% 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 Bastrop County, TX?
Bastrop County is in Zone 9a with an average last frost of February 27. Plan your Onion planting based on this frost date — see the calendar above for exact timing.
What planting zone is Bastrop County, TX?
Bastrop County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 27 and first fall frost is December 1.
Your Bastrop County Garden Planner — Free
A 24-page printable planner built for Bastrop 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.