But before growers over-seed, Johnson said they need to look carefully at soil fertility and residual overgrowth and develop a plan to fix any problems.
"Growers need to look for underlying issues that would cause seedling failure," he said. "Some of those issues include low soil pH and poor fertility. They need to make sure that residual growth from 2013 is no more than 4 inches tall so that the seed can reach the soil surface.
"Also, overseeding alfalfa seed into a field that currently has alfalfa is risky because the currently established alfalfa produces a chemical that hampers the establishment of new alfalfa seedlings."
The timing of over-seeding also is crucial. Johnson said broadcast seeding should be done at green-up because seedlings will have to compete with perennial plants breaking winter dormancy.
Finally, growers need to make careful seed selections, partially based on field history. For example, the weed history of a field would have an effect on seed selection because herbicides used to control broadleaf weeds also kill perennial broadleaf forages. It's also important to choose a seed that mixes well with the forages already growing.