State × crop calendar
Corn planting in Montana.
- Secondary crop
- Zone 4b
- 125-day season
- Last frost May 20
- Row Crop
- Frost Sensitive
Corn 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. Corn 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.
Corn · 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
CornEarliest
May 13
Ideal start
May 20
Ideal end
June 10
Latest
June 24
Soil-temp trigger
Wait for 50°F at 2-inch soil depth — typically 1 week after last frost in northern states; close to last frost in southern states.Harvest window
Typical start
August 18
Typical end
September 17
Harvest timing varies with planting date and seasonal weather — these dates are typical for the ideal planting window.
Growing notes
Corn 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.
Corn is grown in Montana but is not a dominant crop — works for home gardens, food plots, and some commercial production.
Agronomy reference
Corn fundamentals.
Soil-temp minimum
50°F
Soil-temp optimum
60–86°F
Days to maturity
90–120
Water (in/wk)
1–1.5"
Soil pH
6–6.8
Nitrogen demand
high
Growing-degree-day requirement: 2400 GDD (base 50°F) from planting to maturity.
Maturity varies by hybrid relative maturity (RM) — choose RM appropriate for your growing season length.
Common pests to watch
- European corn borer
- Western corn rootworm
- Corn earworm
Pest pressure varies by region and year. Confirm current outbreaks with Montana State University Extension.
Common diseases
- Gray leaf spot
- Northern corn leaf blight
- Tar spot
Resistance varieties shift each year. Check the current variety trial report for your state.
Variety selection
Corn 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 “corn variety trial” or “recommended corn 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.
Corn 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 →