Blog

When to Plant Onion in Fort Bend 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.

Fort Bend County, Texas is in USDA Zone 9b. The average last spring frost is February 14 and the first fall frost is December 8, giving you a growing season of approximately 297 days.

At an elevation of 90 feet, Fort Bend County receives approximately 70.9 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 95°F, so Onion may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — 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.

Fort Bend County, TX (Zone 9b) Year-round
297 days
Last Spring Frost February 14
297 growing days
First Fall Frost December 8

Fort Bend County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.3-6.4

Drainage

Well Drained

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 1.6" 0" ❄️ Dormant
Feb 4.3" 2.5" 1.8" 💧 Light watering
Mar 4.3" 4.9" 0" ✅ Rainfall sufficient
Apr 4.3" 6.6" 0" ✅ Rainfall sufficient
May 4.3" 10.8" 0" ✅ Rainfall sufficient
Jun 4.3" 12.6" 0" ✅ Rainfall sufficient
Jul 4.3" 9" 0" ✅ Rainfall sufficient
Aug 4.3" 7.4" 0" ✅ Rainfall sufficient
Sep 4.3" 7" 0" ✅ Rainfall sufficient
Oct 4.3" 4.8" 0" ✅ Rainfall sufficient
Nov 4.3" 2.1" 2.2" 🚿 Regular watering
Dec 4.3" 1.5" 2.8" 🚿 Regular watering

Water needs are for active growing months only (Feb–Dec in Fort Bend County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Onion Planting Timeline — Fort Bend County, TX

Onion Planting Calendar

Activity When Date Range
Start Indoors January 17 Jan 17 – Jan 31
Transplant Outdoors February 14 Feb 14 – Feb 28
Direct Sow January 24 Jan 24 – Feb 14
Harvest May 16 May 16 – Jul 4
Fall Sowing October 13 Oct 13 – Oct 27

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 9b

📆 Growing Season

297 days in Fort Bend County

Growing Tips for Fort Bend 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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Onion in Fort Bend County, TX?

Fort Bend County is in Zone 9b with an average last frost of February 14. Plan your Onion planting based on this frost date — see the calendar above for exact timing.

What planting zone is Fort Bend County, TX?

Fort Bend County, Texas is in USDA Hardiness Zone 9b. The average last spring frost is February 14 and first fall frost is December 8.

🌱

Your Fort Bend County Garden Planner — Free

A 22-page printable planner built for Fort Bend County (Zone 9b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

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

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.