No herbicides used except pre plant.

This is what we get up here with a discing and follow up with roundup in mid summer. Then plant clover with a light cover crop ( oats) in late summer ( Aug 10). That eliminates the weed competition and gets the clover started with the late summer rains. It then has nearly 3 months of cool moist weather to grow .
This is an exceptional stand...but most we plant are nearly this clean the first year. We get grass in later years, but on all but the poorest sites, the clover is a minimum of a 40% stand for at least 4 years.