You could use a patch kit if you are still looking for a solution, but it would work out cheaper (especially if they are big patches) getting 'canada grass seed' off amazon with a red pack with before and after pics on it. I burnt patches in my lawn last month with lawn sand, and was umming and arghing over seed or the patch kits. Got this seed, just threw it over the patches and left it. Watered in the morning and evening, and the lawn was green again within 7-10 days. I threw seed over the rest of the lawn as well, and now it looks so much better.