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When to Plant Soybeans in Effingham County, IL

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.

Effingham County, Illinois is in USDA Zone 5b. The average last spring frost is April 16 and the first fall frost is October 17, giving you a growing season of approximately 184 days.

At an elevation of 953 feet, Effingham County receives approximately 40.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Soybeans to ensure they mature before fall.

Effingham County, IL (Zone 5b) Moderate season
184 days
Last Spring Frost April 16
184 growing days
First Fall Frost October 17

Effingham County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (44 days to spare)
Transplant: Apr 10 🍅 Harvest: Jul 3 – Aug 28
Recommended (50%) ✓ Fits season (44 days to spare)
Transplant: Apr 16 🍅 Harvest: Jul 9 – Sep 3
Safe Start (90%) ✓ Fits season (45 days to spare)
Transplant: Apr 30 🍅 Harvest: Jul 23 – Sep 17

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 Effingham County

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

Soil pH

Your soil pH (5.8โ€“7.2) overlaps with Soybeans's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

The silt loam soil in Effingham County is excellent for Soybeans โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.9%). Annual compost additions will help Soybeans.

How to Plant Soybeans

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

Succession Planting Soybeans

2
successive plantings in your 184-day season

Sow every 9.1 weeks. Last sowing by Jun 19 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 131 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” 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 โ€” 1.5" 0" โ„๏ธ Dormant
Feb โ€” 1.8" 0" โ„๏ธ Dormant
Mar โ€” 3.1" 0" โ„๏ธ Dormant
Apr 4.3" 3.8" 0.5" ๐Ÿ’ง Light watering
May 4.3" 5.1" 0" โœ… Rainfall sufficient
Jun 4.3" 4.5" 0" โœ… Rainfall sufficient
Jul 4.3" 4.6" 0" โœ… Rainfall sufficient
Aug 4.3" 4.5" 0" โœ… Rainfall sufficient
Sep 4.3" 3.8" 0.5" ๐Ÿ’ง Light watering
Oct 4.3" 3.3" 1" ๐Ÿ’ง Light watering
Nov โ€” 2.9" 0" โ„๏ธ Dormant
Dec โ€” 2.1" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Effingham County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~1,225 GDD — county provides 2,254 GDD Excellent fit

Soybeans Planting Timeline โ€” Effingham County, IL

Soybeans Planting Calendar

Activity When Date Range
Direct Sow April 23 Apr 23 โ€“ May 14
Harvest July 16 Jul 16 โ€“ Sep 10

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

80โ€“120 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 5b

๐Ÿ“† Growing Season

184 days in Effingham County

Growing Tips for Soybeans in Effingham County

Direct sow Soybeans outdoors after April 16 in Effingham County when soil has warmed and frost danger has passed.

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 Effingham County, IL?

Effingham County is in Zone 5b with an average last frost of April 16. Plan your Soybeans planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Effingham County, IL?

Effingham County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 16 and first fall frost is October 17.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Effingham County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Effingham County, IL. Local conditions may vary. Last updated: April 2026.