We need to regrow an existing lawn (6000 sq ft), we can't really afford sod so we were thinking of seeding. Should we kill off the existing crappy turf and weeds first or just seed over it? If we just seed over the existing lawn and weeds will the new seed take over and crowd out the original nasty stuff. We will be seeding with Kentucky blue grass. Any specific type to use? Can we get by with purchasing some horse feeding hay and covering the new seeds to keep them moist or will the hay introduce more crazy weeds and get us right back where we started?