Germination goes down if you get it too deep, to almost zilch if you get it below two inches. My experience has been if you don't see a few seeds on top of the ground, you'd better stop and adjust the drill a notch. In the winner's circle Alfalfa does best in deep, fertile, well-drained soils. It requires a high level of phosphorus for root growth. While less critical, nitrogen and potash are needed in small amounts.
Nitrogen stimulates growth before the plant's development of nitrogen-fixing root nodules.
Boron, useful on established stands, is toxic to seedlings. Soil pH should be six or above. Fertilize according to soil-test results to maintain vigorous, productive stands. Southern States has a good supply of Triple Crown this year, the new variety introduced in limited quantities last year. It's done a good job through the trade territory, but its big hole has been lack of aphanomyces resistance.