September 12, 2008

During early fall, alfalfa plants detect that the amount of sunlight each day is decreasing and that winter is approaching. In response to this signal, the plant growth process changes so the plant can winterize itself.

If you cut alfalfa during this winterizing period, the plant begins to regrow. This reduces its ability to winterize as fully as it would if it hadn’t been cut. While alfalfa cut in late September or early October often survives just fine, it may grow more slowly in spring; however, there are several steps you can take this fall to avoid this delay.

1. Most importantly, make sure your alfalfa gets a chance to grow well for a long time in late summer to build its root nutrient reserves. Allow at least six weeks between the previous cutting and the cut that occurs during winterization. This is even more critical if the field gets cut five or more times this year.

    

2. Thoughtfully select fields to be cut during winterization. Avoid old, thinning fields unless you plan to rotate that field to a different crop next year. Young, healthy alfalfa fields containing varieties with good winter survival ratings are most likely to perform well even after a harvest during winterization.

    

3. Consider waiting to cut until mid-October, after winterization is over or plants are nearly dormant. The stress of regrowth following this extra late cutting usually is small.

Often valuable alfalfa is available to cut this time of year. A careful harvest will help assure it is there again next year.

Bruce Anderson
Extension Forage Specialist