Q: We are planning to seed our all clay backyard with fescue and know that we will have to add topsoil. Do we need to break up the clay before we add topsoil? Is two inches of topsoil enough to go over the clay?
A: I hate to say this but you HAVE to break up the clay before adding the topsoil. Even better would be to break up the clay, add the topsoil and then till it all together. Otherwise the grass roots will grow only in the thin topsoil layer and the lawn will be stressed from drought each summer.