State × crop calendar
Alfalfa planting in Hawaii.
- Limited / marginal
- Zone 11a
- 365-day season
- Last frost January 1
- Forage
- Frost Hardy
Alfalfa planting in Hawaii is shaped by the state's 11a dominant hardiness zone, last frost date around January 1, and a 365-day growing season. Alfalfa can be grown in Hawaii with attention to season length and variety selection — primarily a specialty or experimental crop here.
Planting dates on this page are climatological estimates from USDA frost-date norms and zone-typical planting offsets. Verify against University of Hawaii College of Tropical Agriculture for variety- and county-specific guidance.
Planting calendar — 2026
Frost-anchored windows.
Alfalfa · Hawaii · 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
AlfalfaEarliest
December 11
Ideal start
December 25
Ideal end
January 22
Latest
February 12
Soil-temp trigger
Spring seeding: cool-season germination at 45°F+. Fall seeding: 60-90 days before first hard freeze for establishment.Fall planting
AlfalfaEarliest
October 17
Ideal start
November 1
Ideal end
November 16
Latest
December 1
Soil-temp trigger
Spring seeding: cool-season germination at 45°F+. Fall seeding: 60-90 days before first hard freeze for establishment.Harvest window
Typical start
February 23
Typical end
March 25
Harvest timing varies with planting date and seasonal weather — these dates are typical for the ideal planting window.
Growing notes
Alfalfa is challenging in Hawaii's climate — focus on short-season varieties, raised beds, season extension (row cover, low tunnel), or microclimates with longer growing windows.
Alfalfa can be grown in Hawaii with attention to season length and variety selection — primarily a specialty or experimental crop here.
Agronomy reference
Alfalfa fundamentals.
Soil-temp minimum
45°F
Soil-temp optimum
50–75°F
Days to maturity
60–90
Water (in/wk)
0.7–1"
Soil pH
6.5–7.5
Nitrogen demand
low
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 Hawaii College of Tropical Agriculture.
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 Hawaii 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.
University of Hawaii College of Tropical Agriculture →Search the extension site for “alfalfa variety 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.
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.
Start free trial →