Time of alfalfa seeding is influenced by precipitation patterns, temperature, and cropping patterns. Spring seedings allow for harvest during the seeding year, but weed control usually is required. Late summer and fall seedings usually avoid weed competition and unfavorable summer temperatures and moisture conditions but must allow for adequate seedling development prior to the onset of winter. Late summer and fall seedings must be made early and have sufficient soil moisture to allow enough growth to minimize loss of stand from winter injury. Seeding Alfalfa seed must be placed in contact with moist soil.
Seedlings are unable to emerge from the soil if planted too deep.
Increased seeding rates normally are not economically justified when well-prepared firm seedbeds are used. However, higher seeding rates sometimes are used to compensate for poor soil preparation or seeding methods. Autotoxicity Attempts to reestablish alfalfa immediately following a previous alfalfa crop or to thicken old alfalfa stands sometimes have resulted in establishment failures. Autotoxicity effects are attributed to plant exudates and by-products of decomposition. A period of 2 or more weeks between plowing and seeding or 3 or more weeks after herbicide killing of alfalfa and seeding can be used to avoid autotoxicity.