Blog

When to Plant Onion in Refugio 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.

Refugio County, Texas is in USDA Zone 9a. The average last spring frost is February 16 and the first fall frost is December 6, giving you a growing season of approximately 293 days.

At an elevation of 1,000 feet, Refugio County receives approximately 68.4 inches of rainfall annually with predominantly loam soil. Summer highs average 103ยฐF, 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.

Refugio County, TX (Zone 9a) Year-round
293 days
Last Spring Frost February 16
293 growing days
First Fall Frost December 6

Refugio County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (160 days to spare)
Start indoors: Jan 5 Transplant: Feb 2 🍅 Harvest: May 4 – Jun 22
Recommended (50%) ✓ Fits season (153 days to spare)
Start indoors: Jan 19 Transplant: Feb 16 🍅 Harvest: May 18 – Jul 6
Safe Start (90%) ✓ Fits season (145 days to spare)
Start indoors: Feb 12 Transplant: Mar 12 🍅 Harvest: Jun 11 – Jul 30

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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 60 gal / 100 sq ft
Onion needs ~2,861 GDD — county provides 8,011 GDD Excellent fit

Onion Planting Timeline โ€” Refugio County, TX

Onion Planting Calendar

Activity When Date Range
Start Indoors January 19 Jan 19 โ€“ Feb 2
Transplant Outdoors February 16 Feb 16 โ€“ Mar 2
Direct Sow January 26 Jan 26 โ€“ Feb 16
Fall Sowing October 11 Oct 11 โ€“ Oct 25
Harvest May 18 May 18 โ€“ Jul 6

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

90โ€“120 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 9a

Growing Season

293 days

Growing Tips for Refugio 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

  • Peas
  • Green Beans
  • Asparagus

Level Up Your Garden

Frequently Asked Questions

When should I plant Onion in Refugio County, TX?

Refugio County is in Zone 9a with an average last frost of February 16. Plan your Onion planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Refugio County, TX?

Refugio County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 16 and first fall frost is December 6.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Refugio County gardeners in Zone 9a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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