Alfalfa planting in Idaho.
Alfalfa planting in Idaho is shaped by the state's 5b dominant hardiness zone, last frost date around May 15, and a 130-day growing season. Alfalfa is widely grown in Idaho — commercially significant or common in home gardens and food plots.
Planting dates on this page are climatological estimates from USDA frost-date norms and zone-typical planting offsets. Verify against University of Idaho Extension for variety- and county-specific guidance.
Planting calendar — 2026
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
Spring planting
AlfalfaFall planting
AlfalfaHarvest window
Harvest timing varies with planting date and seasonal weather — these dates are typical for the ideal planting window.
Growing notes
Alfalfa grows well in Idaho's typical climate. Idaho's 130-day growing season and 5b hardiness zone support reliable production with appropriate variety selection.
Alfalfa is widely grown in Idaho — commercially significant or common in home gardens and food plots.
Agronomy reference
Establishment year produces limited harvest. Stand life 4-6 years with proper management. Spring vs. fall seeding strategy varies by region.
Common pests to watch
- Alfalfa weevil
- Potato leafhopper
- Aphids
Pest pressure varies by region and year. Confirm current outbreaks with University of Idaho Extension.
Common diseases
- Sclerotinia crown rot
- Verticillium wilt
- Phytophthora root rot
Resistance varieties shift each year. Check the current variety trial report for your state.
Variety selection
Alfalfa varieties for Idaho live with your extension service.
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.
Search the extension site for “alfalfavariety trial” or “recommended alfalfa 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.
Beyond the harvest
Alfalfa as a hunting food plot.
Alfalfa is the highest-protein forage available to whitetail deer. Early-season alfalfa fields produce concentrated bow-season hunting opportunities, especially in western states with limited natural browse.
Alfalfa 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.