I'm planning on renting a core aerator and my question is how many passes of
> the lawn should I make.
>
> I believe the cores are spaced about 3 inches apart at the cylinder. Do I
> overlap the aerator so the cores are spaced apart 1 and half inches or will
> 3 inches do the job.
Good day Ray. I'd say if your lawn is not overly compacted run it once. If there is a good deal of compaction or your lawn is heavy clay run it twice. After your done you may wish to spread sand over the lawn to fill in the holes. If you have heavy clay, do not do this or you'll make concrete. I personally preferr finely ground compost as a top dressing. Top dressing is not required though. Have fun aerating.