Update on Freeze-Damaged Alfalfa

Update on Freeze-Damaged Alfalfa

April 13, 2007

Almost all alfalfa top growth in the Great Plains and Midwest was killed by the multiple hard freezes. My guess is that anything more than 6 to 8 inches tall will recover a week to 10 days faster if the frozen growth is removed. Shorter plants may not be set back as badly.

Most soils in the region, however, are too wet and/or soft to support either farm equipment or grazing livestock without causing serious damage to alfalfa crowns — probably much more damage than the good that would be achieved by removing the frozen growth. As a result, about the only course of action most people can take is to wait for the plant to begin regrowth on its own. If — and only if — soils are firm enough to support equipment, it also may require a flail type cutter or similar type of cutting equipment to even do a good job of removal since most alfalfa is laying down quite low. An upward vacuuming like action may be necessary to cut off many of the plants.

In the meantime, if you want to determine plant health, try this indoor test. Current weather and soil conditions probably will prevent anyone from replanting or doing field operations for at least a week. To test plant health, dig up plants from several locations in the fields in question, put them into pots (sometimes with the frozen tissue removed), and take them inside to warmer temperatures to see how the plant responds. Live plants probably will start to show new growth by the time fields can be entered again. This will provide more certain answers for specific fields than any other method.

Bruce Anderson
Extension Forage Specialist

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A field of corn.