tkww
Steelhead
Blocking light, cutting off water, and increasing heat. Plastic or cardboard. I've seen people do two layers of plastic, with one suspended a few inches above the other, as a way of increasing the heat (like a double-pane window). Once you're done and you've sod-cut off whatever is left, be sure to water it good over a couple of weeks and see if anything sprouts--I'm thinking of burmuda grass rhizomes. (At which point I would reach for round-up, but to each their own.)