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When to Plant Soybeans in Marshall County, MS

Marshall County, Mississippi Zone 7b May

Marshall County, Mississippi gardeners: here's your May plan

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

Avg. last frost March 27
Avg. first frost October 31
Soil temp (4") 68°F
Watering Low
Pest pressure Moderate
Daylight 13.8 hrs
June prep starts now
  • First harvests: soybeans

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Soybeans (edamame) are a high-protein legume that fixes nitrogen in the soil. Fresh green soybeans harvested at the edamame stage are a nutritious snack.

Marshall County, Mississippi is in USDA Zone 7b. The average last spring frost is March 27 and the first fall frost is October 31, giving you a growing season of approximately 218 days.

At an elevation of 255 feet, Marshall County receives approximately 52.1 inches of rainfall annually with predominantly clay loam soil. Summer highs average 93°F, providing good warmth for Soybeans during the growing season. Clay soil retains moisture well for Soybeans, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Soybeans root diseases.

Marshall County, MS (Zone 7b) Long season
218 days
Last Spring Frost March 27
218 growing days
First Fall Frost October 31

Marshall County Soil Profile

Soil Type

Clay Loam

Soil pH

5.6-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (81 days to spare)
Transplant: Mar 20 🍅 Harvest: Jun 12 – Aug 7
Recommended (50%) ✓ Fits season (78 days to spare)
Transplant: Mar 27 🍅 Harvest: Jun 19 – Aug 14
Safe Start (90%) ✓ Fits season (82 days to spare)
Transplant: Apr 15 🍅 Harvest: Jul 8 – Sep 2

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 Marshall County

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

Soil pH

Your soil pH (5.6–6.3) is more acidic than Soybeans prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

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

How to Plant Soybeans

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Succession Planting Soybeans

3
successive plantings in your 218-day season

Sow every 9.1 weeks. Last sowing by Jul 03 to harvest before frost.

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

Monthly Watering Guide for Soybeans

Soybeans needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Soybeans Needs Rainfall You Supplement Action
Jan 4.5" 0" ❄️ Dormant
Feb 4.7" 0" ❄️ Dormant
Mar 4.3" 4.9" 0" ✅ Rainfall sufficient
Apr 4.3" 3.7" 0.6" 💧 Light watering
May 4.3" 4" 0.3" 💧 Light watering
Jun 4.3" 4.1" 0.2" 💧 Light watering
Jul 4.3" 5.1" 0" ✅ Rainfall sufficient
Aug 4.3" 5.6" 0" ✅ Rainfall sufficient
Sep 4.3" 4.4" 0" ✅ Rainfall sufficient
Oct 4.3" 3.1" 1.2" 💧 Light watering
Nov 3.9" 0" ❄️ Dormant
Dec 4.2" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Oct in Marshall County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Soybeans 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.

Soybeans needs ~1,975 GDD — county provides 4,305 GDD Excellent fit

Soybeans Planting Timeline — Marshall County, MS

Soybeans Planting Calendar

Activity When Date Range
Direct Sow April 3 Apr 3 – Apr 24
Harvest June 26 Jun 26 – Aug 21

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Direct Sow
May
June Harvest
July Harvest
August Harvest
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 7b

📆 Growing Season

218 days in Marshall County

Growing Tips for Soybeans in Marshall County

Direct sow Soybeans outdoors after March 27 in Marshall County when soil has warmed and frost danger has passed.

With Marshall County's clay soil (34% clay), work in 3-4 inches of compost before planting Soybeans. Avoid tilling when soil is wet to prevent compaction.

Common pests for Soybeans in this region include bean beetles and aphids. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow after soil warms to 60F. Plant in blocks rather than rows for better pollination. Harvest for edamame when pods are plump and bright green.

Companion Planting

Good Companions

Avoid Planting Near

  • Onion
  • Garlic

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Soybeans in Marshall County, MS?

Marshall County is in Zone 7b with an average last frost of March 27. Plan your Soybeans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Marshall County, MS?

Marshall County, Mississippi is in USDA Hardiness Zone 7b. The average last spring frost is March 27 and first fall frost is October 31.

🌱

Your Marshall County Garden Planner — Free

A 24-page printable planner built for Marshall 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 Marshall 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.