State × crop calendar
Soybeans planting in Montana.
- Secondary crop
- Zone 4b
- 125-day season
- Last frost May 20
- Row Crop
- Frost Sensitive
Soybeans planting in Montana is shaped by the state's 4b dominant hardiness zone, last frost date around May 20, and a 125-day growing season. Soybeans is grown in Montana but is not a dominant crop — works for home gardens, food plots, and some commercial production.
Planting dates on this page are climatological estimates from USDA frost-date norms and zone-typical planting offsets. Verify against Montana State University Extension for variety- and county-specific guidance.
Planting calendar — 2026
Frost-anchored windows.
Soybeans · Montana · planting calendar
Planting windows shift earlier in southern parts of the state and later in northern parts. Use last frost date in your specific county as the reference.
Planting windows
Earliest → ideal → latest.
Spring planting
SoybeansEarliest
May 20
Ideal start
June 3
Ideal end
June 24
Latest
July 9
Soil-temp trigger
Wait for 50°F minimum soil temp at 2-inch depth. Soybeans planted into colder soil emerge slowly and are vulnerable to seed rot.Harvest window
Typical start
September 11
Typical end
October 31
Harvest timing varies with planting date and seasonal weather — these dates are typical for the ideal planting window.
Growing notes
Soybeans can be successfully grown in Montana with attention to variety selection. The state's 125-day growing season requires choosing varieties appropriate for the growing window.
Soybeans is grown in Montana but is not a dominant crop — works for home gardens, food plots, and some commercial production.
Agronomy reference
Soybeans fundamentals.
Soil-temp minimum
50°F
Soil-temp optimum
60–85°F
Days to maturity
100–150
Water (in/wk)
0.8–1.4"
Soil pH
6–7
Nitrogen demand
low
Growing-degree-day requirement: 2400 GDD (base 50°F) from planting to maturity.
Maturity group system (MG 0 northern through MG 8 southern) is the primary variety selection input — select MG for your latitude.
Common pests to watch
- Soybean aphid
- Bean leaf beetle
- Stink bugs
Pest pressure varies by region and year. Confirm current outbreaks with Montana State University Extension.
Common diseases
- Sudden death syndrome
- White mold
- Soybean cyst nematode
Resistance varieties shift each year. Check the current variety trial report for your state.
Variety selection
Soybeans varieties for Montana live with your extension.
Variety selection
Variety performance is micro-regional and changes with each year's trial cycle. We don't republish variety lists — instead, we point directly at the source.
Montana State University Extension →Search the extension site for “soybeans variety trial” or “recommended soybeans varieties” to find the current report.
Yield varies significantly by variety, soil, fertility, and management. Consult your state extension service for variety performance trials in your region.
Soybeans timing. Live alerts.
Bield: Farm ties weather and soil-temperature stations in your county to crop planting thresholds — get notified the day soil temp clears your target window.
Start free trial →