Question
We bought a house that has a huge lawn full of crabgrass and other weeds. We talked about doing a weed & feed application because what we seed in is overrun by the weeds. If not using chemicals, how do you get rid of the really tough weeds that are way too many to dig out?

Answer
If you do not care for a chemical solution and manually pulling the weeds is not an option, then mechanical methods are your only recourse. Plough or Roto till the area in more than one direction and remove the plant material between each operation. You should be left with a nicely tilled area which you can sod immediately to prevent any of the old material from poking through.