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When to Plant Onion in Kinney County, TX

Kinney County, Texas Zone 9a May

May in the garden — Kinney County, Texas

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Kinney County, Texas.

Avg. last frost February 22
Avg. first frost November 30
Soil temp (4") 73°F
Watering High
Pest pressure High
Daylight 13.5 hrs
  1. Basket week: onion

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

Get ahead of June
  • 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.

Kinney County, Texas is in USDA Zone 9a. The average last spring frost is February 22 and the first fall frost is November 30, giving you a growing season of approximately 281 days.

At an elevation of 1,375 feet, Kinney County receives approximately 52.2 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 101°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.

Kinney County, TX (Zone 9a) Year-round
281 days
Last Spring Frost February 22
281 growing days
First Fall Frost November 30

Kinney County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.4-8.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (145 days to spare)
Start indoors: Jan 16 Transplant: Feb 13 🍅 Harvest: May 15 – Jul 3
Recommended (50%) ✓ Fits season (141 days to spare)
Start indoors: Jan 25 Transplant: Feb 22 🍅 Harvest: May 24 – Jul 12
Safe Start (90%) ✓ Fits season (133 days to spare)
Start indoors: Feb 18 Transplant: Mar 18 🍅 Harvest: Jun 17 – Aug 5

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 Kinney County

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

Soil pH

Your soil pH (7.4–8.6) is more alkaline than Onion prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Kinney County warms quickly in spring but drains fast. Onion will need more frequent watering and regular compost additions to retain nutrients.

Organic Matter

Organic matter is low (1.1%). Add 2-3 inches of compost before planting 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
0.8″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 670 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 3.4" 0" ❄️ Dormant
Feb 4.3" 3.3" 1" 💧 Light watering
Mar 4.3" 3" 1.3" 💧 Light watering
Apr 4.3" 1.7" 2.6" 🚿 Regular watering
May 4.3" 1.3" 3" 🚿 Regular watering
Jun 4.3" 2" 2.3" 🚿 Regular watering
Jul 4.3" 8.2" 0" ✅ Rainfall sufficient
Aug 4.3" 10.4" 0" ✅ Rainfall sufficient
Sep 4.3" 7.6" 0" ✅ Rainfall sufficient
Oct 4.3" 4" 0.3" 💧 Light watering
Nov 4.3" 3.4" 0.9" 💧 Light watering
Dec 3.7" 0" ❄️ Dormant

Water needs are for active growing months only (Feb–Nov in Kinney 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 ~2,704 GDD — county provides 7,261 GDD Excellent fit

Onion Planting Timeline — Kinney County, TX

Onion Planting Calendar

Activity When Date Range
Start Indoors January 25 Jan 25 – Feb 8
Transplant Outdoors February 22 Feb 22 – Mar 8
Direct Sow February 1 Feb 1 – Feb 22
Harvest May 24 May 24 – Jul 12
Fall Sowing October 5 Oct 5 – Oct 19

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9a

📆 Growing Season

281 days in Kinney County

Growing Tips for Onion in Kinney County

Direct sow Onion outdoors after February 22 in Kinney County when soil has warmed and frost danger has passed.

Sandy soil in Kinney County dries quickly — mulch Onion with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 101°F in Kinney County, provide afternoon shade for Onion and water deeply in the morning.

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 Kinney County, TX?

Kinney County is in Zone 9a with an average last frost of February 22. Plan your Onion planting based on this frost date — see the calendar above for exact timing.

What planting zone is Kinney County, TX?

Kinney County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 22 and first fall frost is November 30.

🌱

Your Kinney County Garden Planner — Free

A 24-page printable planner built for Kinney 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 Kinney 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.