Alfalfa growers have to balance the need for tonnage, forage
quality and winter survival when deciding whether to take a late
cutting, say Dan Undersander, University of Wisconsin Extension
forage agronomist, and Bill Bland, Extension climatologist. They
point out that alfalfa must either be cut early enough in fall
to regrow and replenish root carbohydrates and proteins or so
late that the alfalfa doesn’t regrow and use root carbohydrates.
This has resulted in the recommendation of a “no-cut” window
from Sept 1 to killing frost for Wisconsin and several other
states. However, research in Quebec has helped define that
window by indicating that alfalfa needs 500 growing degree days
(GDD) after the last cutting to regrow sufficiently for good
winter survival and yield the next year. On the other extreme,
the Quebec research showed that cutting later in fall is
acceptable if less than 200 GDD accumulate after the cutting.
“It is important to remember that we do not need to wait for a
killing frost to take the la