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When to Plant Onion in Monroe County, MS

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.

Monroe County, Mississippi is in USDA Zone 7b. The average last spring frost is March 23 and the first fall frost is November 6, giving you a growing season of approximately 228 days.

At an elevation of 448 feet, Monroe County receives approximately 54.4 inches of rainfall annually with predominantly clay loam soil. Summer highs average 88ยฐF, 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.

Monroe County, MS (Zone 7b) Long season
228 days
Last Spring Frost March 23
228 growing days
First Fall Frost November 6

Monroe County Soil Profile

Soil Type

Clay Loam

Soil pH

5.4-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (88 days to spare)
Start indoors: Feb 7 Transplant: Mar 14 🍅 Harvest: Jun 13 – Aug 1
Recommended (50%) ✓ Fits season (88 days to spare)
Start indoors: Feb 16 Transplant: Mar 23 🍅 Harvest: Jun 22 – Aug 10
Safe Start (90%) ✓ Fits season (87 days to spare)
Start indoors: Mar 9 Transplant: Apr 13 🍅 Harvest: Jul 13 – Aug 31

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
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Onion needs ~1,680 GDD — county provides 3,648 GDD Excellent fit

Onion Planting Timeline โ€” Monroe County, MS

Onion Planting Calendar

Activity When Date Range
Start Indoors February 16 Feb 16 โ€“ Mar 2
Transplant Outdoors March 23 Mar 23 โ€“ Apr 6
Direct Sow March 9 Mar 9 โ€“ Mar 30
Fall Sowing August 28 Aug 28 โ€“ Sep 11
Harvest June 22 Jun 22 โ€“ Aug 10

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

Month-by-Month Timeline

MonthActivities
January โ€”
February Start Indoors
March Start Indoors Transplant Outdoors Direct Sow
April Transplant Outdoors
May โ€”
June Harvest
July Harvest
August Fall Sowing Harvest
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 7b

Growing Season

228 days

Growing Tips for Monroe 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

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Frequently Asked Questions

When should I plant Onion in Monroe County, MS?

Monroe County is in Zone 7b with an average last frost of March 23. Plan your Onion planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Monroe County, MS?

Monroe County, Mississippi is in USDA Hardiness Zone 7b. The average last spring frost is March 23 and first fall frost is November 6.

๐ŸŒฑ

Plan Your Garden with Confidence

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