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When to Plant Onion in Tishomingo County, MS

Tishomingo County, Mississippi Zone 7b May

Your May planting checklist for Tishomingo County, Mississippi

A quick May briefing for Tishomingo County, Mississippi gardeners — what's urgent, what's next, and what can wait.

Avg. last frost March 30
Avg. first frost October 29
Soil temp (4") 69°F
Watering Low
Pest pressure Moderate
Daylight 13.8 hrs
  1. Indoor seed-starting week for onion

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

Before June arrives, get these ready
  • 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.

Tishomingo County, Mississippi is in USDA Zone 7b. The average last spring frost is March 30 and the first fall frost is October 29, giving you a growing season of approximately 213 days.

At an elevation of 101 feet, Tishomingo County receives approximately 56.9 inches of rainfall annually with predominantly clay loam soil. Summer highs average 90°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.

Tishomingo County, MS (Zone 7b) Long season
213 days
Last Spring Frost March 30
213 growing days
First Fall Frost October 29

Tishomingo County Soil Profile

Soil Type

Clay Loam

Soil pH

5.2-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (76 days to spare)
Start indoors: Feb 15 Transplant: Mar 22 🍅 Harvest: Jun 21 – Aug 9
Recommended (50%) ✓ Fits season (73 days to spare)
Start indoors: Feb 23 Transplant: Mar 30 🍅 Harvest: Jun 29 – Aug 17
Safe Start (90%) ✓ Fits season (79 days to spare)
Start indoors: Mar 12 Transplant: Apr 16 🍅 Harvest: Jul 16 – Sep 3

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 Tishomingo County

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

Soil pH

Your soil pH (5.2–6.5) is more acidic than Onion prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

The clay loam soil in Tishomingo County is excellent for Onion — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Onion.

How to Plant Onion

1"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

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 4.3" 0" ❄️ Dormant
Feb 4.6" 0" ❄️ Dormant
Mar 4.3" 5.2" 0" ✅ Rainfall sufficient
Apr 4.3" 3.8" 0.5" 💧 Light watering
May 4.3" 4.9" 0" ✅ Rainfall sufficient
Jun 4.3" 5.4" 0" ✅ Rainfall sufficient
Jul 4.3" 5.8" 0" ✅ Rainfall sufficient
Aug 4.3" 5.5" 0" ✅ Rainfall sufficient
Sep 4.3" 4" 0.3" 💧 Light watering
Oct 4.3" 3.9" 0.4" 💧 Light watering
Nov 4.7" 0" ❄️ Dormant
Dec 4.6" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Oct in Tishomingo 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 ~1,838 GDD — county provides 3,727 GDD Excellent fit

Onion Planting Timeline — Tishomingo County, MS

Onion Planting Calendar

Activity When Date Range
Start Indoors February 23 Feb 23 – Mar 9
Transplant Outdoors March 30 Mar 30 – Apr 13
Direct Sow March 16 Mar 16 – Apr 6
Harvest June 29 Jun 29 – Aug 17
Fall Sowing August 20 Aug 20 – Sep 3

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 7b

📆 Growing Season

213 days in Tishomingo County

Growing Tips for Onion in Tishomingo County

Direct sow Onion outdoors after March 30 in Tishomingo County when soil has warmed and frost danger has passed.

With Tishomingo County's clay soil (29% clay), work in 3-4 inches of compost before planting Onion. Avoid tilling when soil is wet to prevent compaction.

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 Tishomingo County, MS?

Tishomingo County is in Zone 7b with an average last frost of March 30. Plan your Onion planting based on this frost date — see the calendar above for exact timing.

What planting zone is Tishomingo County, MS?

Tishomingo County, Mississippi is in USDA Hardiness Zone 7b. The average last spring frost is March 30 and first fall frost is October 29.

🌱

Your Tishomingo County Garden Planner — Free

A 24-page printable planner built for Tishomingo County (Zone 7b). 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 Tishomingo County, MS. 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.