January 2, 2013

Alfalfa loves snow. In fact, nothing can increase the chance of alfalfa surviving winter better than a thick blanket of snow.
Our moderate fall weather allowed alfalfa plants to harden well for winter, leaving them with a high concentration of nutrients and a low concentration of water in their roots. This winterized condition enables alfalfa crowns and roots to withstand temperatures down as low as 5 degrees above zero.

This may not sound that cold—after all, air temperatures will get much colder than that—but fortunately, the soil doesn't get as cold as the air above it. When soil is covered with a blanket of snow, the snow acts like a layer of insulation protecting the ground from bitter cold temperatures. Plus, it reduces the rate that the soil and alfalfa roots will dry out. This is why winters with little snow cover can cause more injury to alfalfa stands than those with a full cover, especially if soils are as dry as they are this winter.

Of course, management practices in the fall influence the effect of snow on your alfalfa. Tall stubble also provides some insulation value and will catch more snow. Also, avoiding alfalfa harvest during the so-called risk period from mid-September through mid-October helps alfalfa roots winterize well by building up nutrients and reducing water content.

While you may not like how snow disrupts your daily routine, consider it a blessing for your alfalfa, particularly this winter. 

Bruce Anderson
Extension Forage Specialist