Overseeding to thicken thinned alfalfa stands
The best option with today’s high fertilizer prices and corn value is to turn the stand over to take the legume and rotational credits for corn production and replant alfalfa into new fields.
Some farmers see thin alfalfa (less than 40 stems per square foot) and think about overseeding to improve the stand and yield. Research suggests that the benefits of overseeding on yield are not seen unless the alfalfa stand is less than five plants per square foot, or 40 stems per square foot, and may not be seen even then. Older alfalfa stands with a heavy weed load of species such as dandelion or quackgrass may produce greater return for legume credits and rotation to another crop rather than overseeding to extend the stand life.
Soil test before overseeding to ensure that soil pH and fertility are adequate, else both existing alfalfa and new seedings will have reduced growth due to low soil pH or nutrient deficiency.
Dan Undersander March 9, 2023