When to Plant Soybeans in Simpson County, MS
Simpson County, Mississippi gardeners: here's your May plan
Your garden in Simpson County, Mississippi is working on a schedule, even when you're not. Here's where you should be this May.
To set up a strong June, finish these tasks
- First harvests: soybeans
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.
Simpson County, Mississippi is in USDA Zone 8b. The average last spring frost is March 10 and the first fall frost is November 15, giving you a growing season of approximately 250 days.
At an elevation of 90 feet, Simpson County receives approximately 48.4 inches of rainfall annually with predominantly clay loam soil. Summer highs average 97°F, so Soybeans may need afternoon shade and extra watering during peak heat. Clay soil retains moisture well for Soybeans, but amend with compost to improve drainage and prevent root rot.
Simpson County Soil Profile
Soil Type
Clay Loam
Soil pH
5.6-6.8
Drainage
Well Drained
Plant Planting Risk Windows
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 Simpson County
How your county's soil matches Soybeans's growing requirements.
Soil pH
Your soil pH (5.6–6.8) overlaps with Soybeans's range (6.0–7.0), though not a perfect match.
Soil Texture
The clay loam soil in Simpson County is excellent for Soybeans — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.2%). Annual compost additions will help Soybeans.
How to Plant Soybeans
Succession Planting Soybeans
Sow every 9.1 weeks. Last sowing by Jul 18 to harvest before frost.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
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 | — | 4.3" | 0" | ❄️ Dormant |
| Feb | — | 4" | 0" | ❄️ Dormant |
| Mar | 4.3" | 4.3" | 0" | ✅ Rainfall sufficient |
| Apr | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| May | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Jun | 4.3" | 4.9" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 4.8" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Sep | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| Oct | 4.3" | 2.9" | 1.4" | 💧 Light watering |
| Nov | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| Dec | — | 3.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Simpson 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 Planting Timeline — Simpson County, MS
Soybeans Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | March 17 | Mar 17 – Apr 7 |
| Harvest | June 9 | Jun 9 – Aug 4 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Direct Sow |
| 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 · Only during dry spells
📅 Days to Maturity
80–120 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 8b
📆 Growing Season
250 days in Simpson County
Growing Tips for Soybeans in Simpson County
Direct sow Soybeans outdoors after March 10 in Simpson County when soil has warmed and frost danger has passed.
With Simpson County's clay soil (32% clay), work in 3-4 inches of compost before planting Soybeans. Avoid tilling when soil is wet to prevent compaction.
With summer highs reaching 97°F in Simpson County, provide afternoon shade for Soybeans and water deeply in the morning.
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
Check more plant combinations with our Companion Planting Checker →
Soybeans in Other Locations
Frequently Asked Questions
When should I plant Soybeans in Simpson County, MS?
Simpson County is in Zone 8b with an average last frost of March 10. Plan your Soybeans planting based on this frost date — see the calendar above for exact timing.
What planting zone is Simpson County, MS?
Simpson County, Mississippi is in USDA Hardiness Zone 8b. The average last spring frost is March 10 and first fall frost is November 15.
Your Simpson County Garden Planner — Free
A 24-page printable planner built for Simpson County (Zone 8b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.