A fall alfalfa harvest: should you do it on your farm? If you are short on forage supplies, the answer may be yes.
Alfalfa stores energy in its roots and crowns. These energy reserves are used by the plant to survive over winter, to develop cold tolerance, and to initiate spring growth and growth after each cutting. Alfalfa needs to be either cut early enough in the fall to regrow and replenish root carbohydrates and proteins or late enough so it does not grow back and use stored root carbohydrates. This is vital for winter survival.
This knowledge has resulted in a "no cut" window, generally from mid-September to mid-October, depending on where you are in the country and climate. Forage quality of alfalfa changes little during September, according to Dan Undersander, University of Wisconsin-Madison Extension agronomist. Therefore, harvesting versus waiting should be based on the likelihood of winter injury or survival if the stand is to be kept.
If a fall harvest of alfalfa is done, choose fields that are well established and well drained. Soil should be fertilized, especially with potassium, to aid in winter survival. Cutting 4 inches or higher could provide some insulation and snow retention, adding winter protection.
A fall cutting of alfalfa will almost certainly reduce first crop yields for next year, and alfalfa harvested in October is usually less than one dry matter ton per acre. Still, this trade-off may be worth it when compared to the alternative of buying high-priced forages if you are going to need feed between now and next harvest season
