Whether you should harvest hail-damaged alfalfa or red clover right away or follow your normal cutting schedule depends on the amount of damage, the crop’s maturity stage and other factors, says Dan Undersander, University of Wisconsin Extension forage agronomist.
Hail damage ranges from some terminal bud and leaf damage to complete defoliation, he says, and usually is somewhere in between the two extremes. If the terminal (highest) bud on a stem is damaged, growth is stopped and regrowth must begin from buds farther down the stem or from crown buds.
If the crop is within two weeks of a planned cutting and lodged from wind and rain that came with the hail, wait four days and cut it, Undersander advises.
“When harvesting lodged alfalfa or red clover, our experience has been that disc mowers will pick up more forage than sicklebar mowers,” he says. “Harvesting against the direction the forage is leaning will allow more to be harvested. With both mower types, tilt the cutter bar or discs forward to increase forage picked up. When using a sicklebar mower one can additionally move the reel forward and down and increase reel speed to help pick up downed forage.”
If the crop isn’t lodged but more than 50% of the terminal buds are damaged, harvest it immediately because any additional growth will be from new stems that will be better-utilized as part of the next cutting.
If it’s within two weeks of a normal cutting but less than 50% of the terminal buds are damaged, wait and harvest it at the normal time, he says. Yield will be reduced but undamaged stems will continue to grow and add to yield.
Finally, if either hail-damaged crop is more than two weeks from harvest maturity (generally less than 12” tall), let it regrow from new shoots and harvest it at the normal height and quality.
For new seedings, first determine whether the seedlings have developed crowns. Those without crowns, usually less than 3-4” tall, and with damaged terminal buds will die. Count the remaining plants and keep the stand if there are more than 25 per square foot, Undersander advises.