Roundup Ready (RR) alfalfa varieties have been widely available for several years in Kentucky, but we now have enough yield data to accurately compare RR variety performance. Look on page 1 of the “2016 Long-Term Summary Report2016 Long-Term Summary Report” to choose the best variety to purchase. Many hay producers tell me that they would like to plant a RR variety, but they also want a mixed grass stand. In this case, simply plant a RR variety as a pure stand and clean up weeds with Roundup for the first 1 to 2 years. Then interseed orchardgrass or another grass species in the fall for a weed-free mixed alfalfa/grass stand. One producer told me he sprayed his mixed hay field with Roundup in year 4 (killing weeds but also the orchardgrass) and then interseeded orchardgrass again that fall producing a vigorous weed-free mixed alfalfa/grass stand for 3 more years.