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When to Plant Onion in Houston 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.

Houston County, Texas is in USDA Zone 8a. The average last spring frost is March 2 and the first fall frost is November 23, giving you a growing season of approximately 266 days.

At an elevation of 379 feet, Houston County receives approximately 59.2 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 94ยฐF, providing good warmth for Onion during the growing season. Sandy soil warms quickly in spring โ€” great for early planting โ€” but Onion will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Onion root diseases.

Houston County, TX (Zone 8a) Long season
266 days
Last Spring Frost March 2
266 growing days
First Fall Frost November 23

Houston County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.8-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (130 days to spare)
Start indoors: Jan 13 Transplant: Feb 17 🍅 Harvest: May 19 – Jul 7
Recommended (50%) ✓ Fits season (126 days to spare)
Start indoors: Jan 26 Transplant: Mar 2 🍅 Harvest: Jun 1 – Jul 20
Safe Start (90%) ✓ Fits season (120 days to spare)
Start indoors: Feb 19 Transplant: Mar 26 🍅 Harvest: Jun 25 – Aug 13

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
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 185 gal / 100 sq ft
Drought risk

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

Onion needs ~2,152 GDD — county provides 5,453 GDD Excellent fit

Onion Planting Timeline โ€” Houston County, TX

Onion Planting Calendar

Activity When Date Range
Start Indoors January 26 Jan 26 โ€“ Feb 9
Transplant Outdoors March 2 Mar 2 โ€“ Mar 16
Direct Sow February 16 Feb 16 โ€“ Mar 9
Fall Sowing September 14 Sep 14 โ€“ Sep 28
Harvest June 1 Jun 1 โ€“ Jul 20

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

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Start Indoors Direct Sow
March Transplant Outdoors Direct Sow
April โ€”
May โ€”
June Harvest
July Harvest
August โ€”
September Fall Sowing
October โ€”
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 8a

Growing Season

266 days

Growing Tips for Houston 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 Houston County, TX?

Houston County is in Zone 8a with an average last frost of March 2. Plan your Onion planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Houston County, TX?

Houston County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 2 and first fall frost is November 23.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Houston County gardeners in Zone 8a 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 Houston County, TX. Local conditions may vary. Last updated: April 2026.