State × crop calendar
Alfalfa planting in New Hampshire.
- Primary crop
- Zone 5b
- 140-day season
- Last frost May 15
- Forage
- Frost Hardy
Alfalfa planting in New Hampshire is shaped by the state's 5b dominant hardiness zone, last frost date around May 15, and a 140-day growing season. Alfalfa is widely grown in New Hampshire — 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 UNH Cooperative Extension for variety- and county-specific guidance.
Planting calendar — 2026
Frost-anchored windows.
Alfalfa · New Hampshire · 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
April 24
Ideal start
May 8
Ideal end
June 5
Latest
June 26
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
July 18
Ideal start
August 2
Ideal end
August 17
Latest
September 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
July 7
Typical end
August 6
Harvest timing varies with planting date and seasonal weather — these dates are typical for the ideal planting window.
Growing notes
Alfalfa grows well in New Hampshire's typical climate. New Hampshire's 140-day growing season and 5b hardiness zone support reliable production with appropriate variety selection.
Alfalfa is widely grown in New Hampshire — commercially significant or common in home gardens and food plots.
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 UNH Cooperative 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 New Hampshire 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.
UNH Cooperative Extension →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 →