Answer: You can dig it out by hand or cut it off in strips or layers using a rented sod cutter machine. You can kill it with herbicide containing glyphosate, carefully read and follow all of the label directions if you do this. Smothering with plastic also solarizes the soil which is not usually recommended. You could however smother it with several layers of dampened newspaper (overlapped at the edges to exclude light) and then topped with a thick layer of organic mulch. If you did that now you could turn the soil over (and dig in whatever is left of the sod, newspaper and mulch) and plant in the fall. This last method is beneficial in that you preserve all of your topsoil and the dead grass, paper and mulch serve as a sources of organic matter to help prepare the soil for planting flowers. I hope this gives you some ideas.
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