2026 Planting Guide
Spring cropWhen to Plant Soybeans in Illinois
Complete guide to growing soybeans in Illinois with optimal planting dates, recommended varieties, soil requirements, pest management, and harvest timing. Data sourced from USDA and state extension services.
Monthly Planting Calendar
Visual overview of the soybeans growing season in Illinois. Red diamond markers indicate frost date boundaries.
Quick Facts
Min. Soil Temp
50°F (10°C) minimum
Growing Period
100-140 days
From planting to harvest
Last Spring Frost
April 20
Wait until after this date
First Fall Frost
October 12
Harvest before this date
Monthly Task Timeline
Month-by-month guide for managing soybeans in Illinois.
January - March
Off-seasonCover crop planting, soil testing, equipment maintenance, and planning for next season.
April - June
PlantPrepare soil, apply starter fertilizer, and sow seeds at recommended depth and spacing.
July - August
Grow & MonitorIrrigate as needed, scout for pests, apply side-dress fertilizer, and manage weeds.
September - October
HarvestCheck maturity indicators, schedule equipment, harvest at optimal moisture content.
November - December
Off-seasonCover crop planting, soil testing, equipment maintenance, and planning for next season.
Best Soybeans Varieties for Illinois
These varieties have proven performance in Illinois's climate and soil conditions. Always source certified seed from reputable dealers.
| # | Variety | Best For |
|---|---|---|
| 1 | Pioneer P25A70X | Illinois climate |
| 2 | Asgrow AG30X0 | Illinois climate |
| 3 | DeKalb DKXF30-20 | Illinois climate |
Growing Tips for Illinois
Region-specific advice from agricultural extension services and experienced Illinois farmers.
Illinois is the #1 soybean producer — use adapted maturity groups (2.5-3.5)
Sudden death syndrome (SDS) — use resistant varieties + seed treatments
Double-crop soybeans after wheat harvest in southern IL
Pest & Disease Watch
Monitor for these threats throughout the growing season. Integrated Pest Management (IPM) is recommended.
Soybean aphid
Scout regularly and use integrated pest management
Bean leaf beetle
Scout regularly and use integrated pest management
Spider mites
Scout regularly and use integrated pest management
Stink bugs
Scout regularly and use integrated pest management
Soybean cyst nematode
Scout regularly and use integrated pest management
Companion Planting
These plants grow well alongside soybeans, improving pest control, pollination, and nutrient availability.
Frost Dates
Last Spring Frost
April 20
Wait until after this date before planting frost-sensitive crops outdoors.
First Fall Frost
October 12
Plan to complete harvest of warm-season crops before this date arrives.
Frequently Asked Questions
When is the best time to plant soybeans in Illinois?
The optimal planting window for soybeans in Illinois is April 25 to June 1. Soil temperature should reach at least 50°F (10°C) minimum before planting. The total growing period is 100-140 days.
What varieties of soybeans grow best in Illinois?
The best varieties for Illinois include Pioneer P25A70X, Asgrow AG30X0, DeKalb DKXF30-20. These varieties are adapted to local climate and soil conditions and have proven performance records.
When can I harvest soybeans in Illinois?
The harvest window for soybeans in Illinois is typically September 20 to October 30. The crop takes 100-140 days from planting to reach maturity.
Get planting reminders for Soybeans in Illinois
Sign up for free alerts when it's time to plant, fertilize, and harvest.
Data Sources
Data sourced from USDA NASS Crop Planting Dates, Illinois Cooperative Extension Service, and NOAA frost date records. Last updated: March 2026.
Planting dates are averages and may vary by county, elevation, and local microclimate. Always consult your local extension office for the most precise recommendations.