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When to Plant Onion in Jackson 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.

Jackson County, Texas is in USDA Zone 9a. The average last spring frost is February 21 and the first fall frost is December 5, giving you a growing season of approximately 287 days.

At an elevation of 286 feet, Jackson County receives approximately 64.3 inches of rainfall annually with predominantly loam soil. Summer highs average 103ยฐF, so Onion may need afternoon shade and extra watering during peak heat. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Onion root diseases.

Jackson County, TX (Zone 9a) Year-round
287 days
Last Spring Frost February 21
287 growing days
First Fall Frost December 5

Jackson County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (149 days to spare)
Start indoors: Jan 11 Transplant: Feb 8 🍅 Harvest: May 10 – Jun 28
Recommended (50%) ✓ Fits season (147 days to spare)
Start indoors: Jan 24 Transplant: Feb 21 🍅 Harvest: May 23 – Jul 11
Safe Start (90%) ✓ Fits season (139 days to spare)
Start indoors: Feb 14 Transplant: Mar 14 🍅 Harvest: Jun 13 – Aug 1

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
0.4″/week
Watering frequency 1-2 times/week
Season total 929 gal / 100 sq ft
Onion needs ~2,861 GDD — county provides 7,848 GDD Excellent fit

Onion Planting Timeline โ€” Jackson County, TX

Onion Planting Calendar

Activity When Date Range
Start Indoors January 24 Jan 24 โ€“ Feb 7
Transplant Outdoors February 21 Feb 21 โ€“ Mar 7
Direct Sow January 31 Jan 31 โ€“ Feb 21
Fall Sowing October 10 Oct 10 โ€“ Oct 24
Harvest May 23 May 23 โ€“ Jul 11

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

Month-by-Month Timeline

MonthActivities
January Start Indoors Direct Sow
February Start Indoors Transplant Outdoors Direct Sow
March Transplant Outdoors
April โ€”
May Harvest
June Harvest
July Harvest
August โ€”
September โ€”
October Fall Sowing
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 9a

Growing Season

287 days

Growing Tips for Jackson 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 Jackson County, TX?

Jackson County is in Zone 9a with an average last frost of February 21. Plan your Onion planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Jackson County, TX?

Jackson County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 21 and first fall frost is December 5.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Jackson County gardeners in Zone 9a 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 Jackson County, TX. Local conditions may vary. Last updated: April 2026.