1/3 of the blade rule out the window if.....

[GripB]

your supposed to cut you grass down as low as possible prior to aerating. I cut my grass at 3 3/4" on Monday. Should I cut today an inch lower? Then on Friday an inch lower and aerate Saturday? I know it's not healthy to cut more than a 1/3 of the blade. So, for a cut or two, will it hurt my grass in any way?

[RichmondR]

If you cut at 3 3/4 on Monday you are probably already at 4 1/2 inches. I would just cut it at 3 1/2 or 3 1/4. I have never had any trouble getting good plugs on bluegrass at that height assuming the lawn is fairly moist and not dried out, and I am using good equipment (I generally use a BlueBird tow behind aerator -- the one where you put the jugs of water on top). That equipment is so heavy that a half inch of grass isn't going to make any difference.

Good luck.

[GripB]

I forgot to mention I'm overseeding also. Hence the question on grass height.