The problem with Round up and glycophosphate is that it has been used for years and some pest plants are now resistant insome areas. In Argentina, Johnson grass is now immune. In the eastern US there are several weeds that are either very resistant or immune to Round Up and other herbicides. At our three places we plant in the spring before the grasses get established, we plant thick. For the fall planting we wait until the native grasses are dormant-no weed problems at all. I ain't a production farmer, i plant food plots for game animals.