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When to Plant Onion in Bastrop 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.

Bastrop County, Texas is in USDA Zone 8b. 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 91ยฐF, 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, TX (Zone 8b) Year-round
277 days
Last Spring Frost February 27
277 growing days
First Fall Frost December 1

Bastrop County Soil Profile

Soil Type

Clay

Soil pH

7.2-7.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (139 days to spare)
Start indoors: Jan 9 Transplant: Feb 13 🍅 Harvest: May 15 – Jul 3
Recommended (50%) ✓ Fits season (137 days to spare)
Start indoors: Jan 23 Transplant: Feb 27 🍅 Harvest: May 29 – Jul 17
Safe Start (90%) ✓ Fits season (126 days to spare)
Start indoors: Feb 15 Transplant: Mar 22 🍅 Harvest: Jun 21 – Aug 9

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 (7.2โ€“7.9) is more alkaline than Onion prefers (6.0โ€“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

1"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 412 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Onion needs ~1,916 GDD — county provides 5,073 GDD Excellent fit

Onion Planting Timeline โ€” Bastrop County, TX

Onion Planting Calendar

Activity When Date Range
Start Indoors January 23 Jan 23 โ€“ Feb 6
Transplant Outdoors February 27 Feb 27 โ€“ Mar 13
Direct Sow February 13 Feb 13 โ€“ Mar 6
Fall Sowing September 22 Sep 22 โ€“ Oct 6
Harvest May 29 May 29 โ€“ Jul 17

Plant 1" deep ยท 6" apart ยท Rows 12" apart

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Start Indoors Transplant Outdoors Direct Sow
March Transplant Outdoors Direct Sow
April โ€”
May Harvest
June Harvest
July Harvest
August โ€”
September Fall Sowing
October Fall Sowing
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

90โ€“120 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 8b

๐Ÿ“† 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

  • Peas
  • Green Beans
  • Asparagus

Level Up Your Garden

Frequently Asked Questions

When should I plant Onion in Bastrop County, TX?

Bastrop County is in Zone 8b with an average last frost of February 27. Plan your Onion planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Bastrop County, TX?

Bastrop County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is February 27 and first fall frost is December 1.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Bastrop County gardeners in Zone 8b organize planting dates, track what's growing, and never miss a planting window.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Bastrop County, TX. Local conditions may vary. Last updated: April 2026.