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When to Plant Onion in Fayette County, TX

Fayette County, Texas Zone 9a May

This month in Fayette County, Texas

We've pulled the most time-sensitive tasks for Fayette County, Texas this May and put them front and centre. Tackle them in order.

Avg. last frost February 27
Avg. first frost November 28
Soil temp (4") 72°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. Start harvesting onion

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

Coming up in June — start thinking about
  • First harvests: onion

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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.

Fayette County, Texas is in USDA Zone 9a. The average last spring frost is February 27 and the first fall frost is November 28, giving you a growing season of approximately 274 days.

At an elevation of 57 feet, Fayette County receives approximately 70 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.

Fayette County, TX (Zone 9a) Year-round
274 days
Last Spring Frost February 27
274 growing days
First Fall Frost November 28
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Fayette County Soil Profile

Soil Type

Clay

Soil pH

6.8-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (135 days to spare)
Start indoors: Jan 17 Transplant: Feb 14 🍅 Harvest: May 16 – Jul 4
Recommended (50%) ✓ Fits season (134 days to spare)
Start indoors: Jan 30 Transplant: Feb 27 🍅 Harvest: May 29 – Jul 17
Safe Start (90%) ✓ Fits season (129 days to spare)
Start indoors: Feb 23 Transplant: Mar 23 🍅 Harvest: Jun 22 – Aug 10

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 Fayette County

How your county's soil matches Onion's growing requirements.

Soil pH

Your soil pH (6.8–8.2) is more alkaline than Onion prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

Heavy clay soil (48% clay) in Fayette County compacts easily and drains slowly. Amend with compost and avoid working soil when wet.

Organic Matter

Organic matter is moderate (2.8%). Annual compost additions will help Onion.

How to Plant Onion

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

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

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 1.7" 0" ❄️ Dormant
Feb 4.3" 2.8" 1.5" 💧 Light watering
Mar 4.3" 4" 0.3" 💧 Light watering
Apr 4.3" 8" 0" ✅ Rainfall sufficient
May 4.3" 10.4" 0" ✅ Rainfall sufficient
Jun 4.3" 11.8" 0" ✅ Rainfall sufficient
Jul 4.3" 8.3" 0" ✅ Rainfall sufficient
Aug 4.3" 8.6" 0" ✅ Rainfall sufficient
Sep 4.3" 6" 0" ✅ Rainfall sufficient
Oct 4.3" 4.2" 0.1" 💧 Light watering
Nov 4.3" 2.6" 1.7" 💧 Light watering
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (Feb–Nov in Fayette 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 needs ~1,916 GDD — county provides 5,018 GDD Excellent fit

Onion Planting Timeline — Fayette 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 3 Oct 3 – Oct 17

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

Month-by-Month Timeline

MonthActivities
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
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9a

📆 Growing Season

274 days in Fayette County

Growing Tips for Onion in Fayette County

Direct sow Onion outdoors after February 27 in Fayette County when soil has warmed and frost danger has passed.

With Fayette County's clay soil (48% 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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Onion in Fayette County, TX?

Fayette 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 Fayette County, TX?

Fayette County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 27 and first fall frost is November 28.

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Your Fayette County Garden Planner — Free

A 24-page printable planner built for Fayette 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.

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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 Fayette County, TX. Local conditions may vary. Last updated: May 2026.

Sources & credits

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