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When to Plant Onion in LaSalle Parish, LA

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.

LaSalle Parish, Louisiana is in USDA Zone 8b. The average last spring frost is March 2 and the first fall frost is November 19, giving you a growing season of approximately 262 days.

At an elevation of 262 feet, LaSalle Parish receives approximately 52.2 inches of rainfall annually with predominantly loam soil. Summer highs average 95ยฐF, 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.

LaSalle Parish, LA (Zone 8b) Long season
262 days
Last Spring Frost March 2
262 growing days
First Fall Frost November 19

LaSalle Parish Soil Profile

Soil Type

Loam

Soil pH

6.2-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (126 days to spare)
Start indoors: Jan 16 Transplant: Feb 20 🍅 Harvest: May 22 – Jul 10
Recommended (50%) ✓ Fits season (122 days to spare)
Start indoors: Jan 26 Transplant: Mar 2 🍅 Harvest: Jun 1 – Jul 20
Safe Start (90%) ✓ Fits season (128 days to spare)
Start indoors: Feb 14 Transplant: Mar 21 🍅 Harvest: Jun 20 – Aug 8

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
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 381 gal / 100 sq ft
Onion needs ~2,231 GDD — county provides 5,567 GDD Excellent fit

Onion Planting Timeline โ€” LaSalle Parish, LA

Onion Planting Calendar

Activity When Date Range
Start Indoors January 26 Jan 26 โ€“ Feb 9
Transplant Outdoors March 2 Mar 2 โ€“ Mar 16
Direct Sow February 16 Feb 16 โ€“ Mar 9
Fall Sowing September 10 Sep 10 โ€“ Sep 24
Harvest June 1 Jun 1 โ€“ Jul 20

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

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Start Indoors Direct Sow
March Transplant Outdoors Direct Sow
April โ€”
May โ€”
June Harvest
July Harvest
August โ€”
September Fall Sowing
October โ€”
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 8b

Growing Season

262 days

Growing Tips for LaSalle Parish

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

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Frequently Asked Questions

When should I plant Onion in LaSalle Parish, LA?

LaSalle Parish is in Zone 8b with an average last frost of March 2. Plan your Onion planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is LaSalle Parish, LA?

LaSalle Parish, Louisiana is in USDA Hardiness Zone 8b. The average last spring frost is March 2 and first fall frost is November 19.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help LaSalle Parish gardeners in Zone 8b 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 LaSalle Parish, LA. Local conditions may vary. Last updated: April 2026.