“How thin is too thin to keep a new alfalfa seeding?” That’s the question that Marvin Hall, Penn State University Extension forage specialist, has fielded from several growers who have complained of having very thin new alfalfa stands.

Hall recommends 15 plants/sq ft as a bare-minimum number of plants in new seedings. “If the numbers drop below that threshold, the stand will not yield as well as it could, stand longevity may be compromised and weed competition may be a greater problem.”

That minimum plant count will probably yield as well as much thicker stands, says Hall. He used 20 years of data to develop a table showing the yields from various plant densities in the seeding year and first second-year cutting. The table shows that seedings with plant densities of 16 alfalfa plants/sq ft produced less yield than thicker stands only in the seeding year’s first harvest.