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When to Plant Onion in Jack 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.

Jack County, Texas is in USDA Zone 7b. The average last spring frost is March 26 and the first fall frost is November 9, giving you a growing season of approximately 228 days.

At an elevation of 2,081 feet, Jack County receives approximately 66.9 inches of rainfall annually with predominantly clay soil. Summer highs average 89Β°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.

Jack County, TX (Zone 7b) Long season
228 days
Last Spring Frost March 26
228 growing days
First Fall Frost November 9

Jack County Soil Profile

Soil Type

Clay

Soil pH

7.3-7.6

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 β€” 2" 0" ❄️ Dormant
Feb β€” 2.3" 0" ❄️ Dormant
Mar 4.3" 3.7" 0.6" πŸ’§ Light watering
Apr 4.3" 8" 0" βœ… Rainfall sufficient
May 4.3" 9.7" 0" βœ… Rainfall sufficient
Jun 4.3" 9.6" 0" βœ… Rainfall sufficient
Jul 4.3" 8.5" 0" βœ… Rainfall sufficient
Aug 4.3" 7.6" 0" βœ… Rainfall sufficient
Sep 4.3" 6.7" 0" βœ… Rainfall sufficient
Oct 4.3" 4.3" 0" βœ… Rainfall sufficient
Nov 4.3" 2.6" 1.7" πŸ’§ Light watering
Dec β€” 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Jack County). Supplement amounts are based on average rainfall β€” actual needs vary with temperature, soil, and mulching.

Onion Planting Timeline β€” Jack County, TX

Onion Planting Calendar

Activity When Date Range
Start Indoors February 19 Feb 19 – Mar 5
Transplant Outdoors March 26 Mar 26 – Apr 9
Direct Sow March 12 Mar 12 – Apr 2
Harvest June 25 Jun 25 – Aug 13
Fall Sowing August 31 Aug 31 – Sep 14

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

Month-by-Month Timeline

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

Growing Conditions

β˜€οΈ Sun

Full Sun (6-8+ hours)

πŸ’§ Water

Moderate β€” regular watering

πŸ“… Days to Maturity

90–120 days

πŸ§ͺ Soil pH

Needs 6–7 Β· Your soil: N/A

πŸ—ΊοΈ USDA Zone

Zone 7b

πŸ“† Growing Season

228 days in Jack County

Growing Tips for Jack 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 Jack County, TX?

Jack County is in Zone 7b with an average last frost of March 26. Plan your Onion planting based on this frost date β€” see the calendar above for exact timing.

What planting zone is Jack County, TX?

Jack County, Texas is in USDA Hardiness Zone 7b. The average last spring frost is March 26 and first fall frost is November 9.

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Plan Your Garden with Confidence

Get our free Garden Planner β€” designed to help Jack County gardeners in Zone 7b 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 Jack County, TX. Local conditions may vary. Last updated: April 2026.