Sept. 12, 2014

Many alfalfa growers may be looking at good growth they'd like to harvest before winter without affecting the plant's natural winterization process and survival.

During early fall, alfalfa plants detect that the amount of sunlight each day is getting less. This tells them that winter is coming so they change their growth process and start winterization. Alfalfa cut during this winterizing period will begin to regrow. This reduces its ability to winterize as fully as it would if it hadn't been cut.

From experience we know alfalfa cut in late September or early October can survive given the right conditions, although spring growth may be a little slower. Following are some guidelines to help increase the chance your cut alfalfa survives and grows well next spring.

First and foremost, make sure your alfalfa grows well for a long time in late summer so it can build its root nutrient reserves.  Allow at least six weeks between your previous cutting and the cut that occurs during winterization. This is especially critical if the field gets cut five or more times this year.

Second, 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 cutting during winterization.
              
Lastly, 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 very small.

Valuable alfalfa often is available to cut this time of year.  Careful harvest will help assure it also is there next year.

Bruce Anderson
Extension Forage Specialist