To prepare your lawn for overseeding, cut the grass short, employing the lowest setting on your backyard. Don’t forget to reset the blades into a higher setting following the overseeding is full and then resume a normal mowing height since you typically don’t need to cut the grass this short. If cutting your yard before overseeding, bag the clippings. What is overseeding a yard? Overseeding is the process of spreading fresh grass seed throughout your present turf. It doesn’t call for complete elimination of the other turf. The new seeds simply fill in the gaps where your turf requires additional fullness.