Proper Fall Harvesting Protects Hay and Alfalfa Stands

By Blake Jackson

Proper fall management is critical for maintaining healthy hay and forage stands through winter and ensuring strong growth the following season.

According to Justin Brackenrich, Leanna Duppstadt, Paul D. Esker, and Adriana Murillo-Williams of Penn State Extension, harvest decisions made in autumn can significantly influence stand longevity, root development, and future yields.

One of the most important factors is carbohydrate storage. Alfalfa stores energy in its roots and crown, while cool-season grasses store carbohydrates in lower stems and tillers. These reserves help plants survive winter and support spring regrowth.

To protect those reserves, producers should leave at least 4 inches of stubble on both alfalfa and grass fields before the first frost. Adequate leaf area allows plants to continue photosynthesis and rebuild energy reserves before dormancy.

Root health is also essential. Excessive cutting can reduce root growth because plants rely on leaf tissue to generate energy.

Removing too much foliage restricts the plant’s ability to absorb water and nutrients and can slow or prevent recovery. Maintaining proper harvest heights helps preserve root mass and supports healthy regrowth.

Disease management should also be considered in the fall. Crop residues can harbor pathogens that survive the winter, and infect forage stands the following season.

Proper harvest scheduling and reducing infected plant material can help limit diseases such as crown rust, stem rust, leaf rust, and brown stripe.

For grass fields, winter survival generally depends on maintaining 4 to 5 inches of stubble and ensuring adequate phosphorus and potassium levels.

Cool-season grasses typically continue growing until temperatures remain near 25°F for extended periods, making fall management especially important.

Alfalfa requires additional attention. Traditional recommendations suggest making the final harvest 4 to 6 weeks before a killing frost to allow time for recovery and nutrient storage.

While newer winter-hardy varieties may tolerate slightly later harvests, producers should carefully evaluate stand age, plant vigor, and overall risk. Older stands and fields that have not been allowed to flower during the season are generally more vulnerable to winter injury.

Although late-season cutting may provide additional forage, it can also reduce spring yields, particularly the first cutting. Growers should balance potential forage gains against the risks to stand health and long-term productivity when making final harvest decisions.

Photo Credit: leanna-duppstadt