I am planting a lawn in a yard that has a clay subsoil and tends towards dampness. The difficulity with trying to establish subsoil drainage is that the clay starts at about 16", and only God knows where it stops! I do not have a backhoe, nor an hydraulic auger for exploration. I pretty much have to work with what I've got, and I want a lawn so we can walk and sit on the area. One suggestion I read for helping with soil percolation is to plant "Native, long-rooted grasses". I have done some searching, but I haven't been able to find any names for these grasses, or local sources of seed. The grass seed at Rona looks like a catch-all mix. Any shared knowledge or recommendation would be greatly appreciated. Thanks!