Question
zip code :43082 - Ohio
Question is: I recently moved from Atlanta GA where I had warm season lawn and know that every March/April you should start off the season by scalping your bermuda grass to 1/2"-1" in length.  
So with blue grass/fescue in cool season lawns when should I start the season and should I start by cutting the grass short to begin with ?  
Should I over seed ?

Answer
Bermuda is a prostrate growing grass which benefit from a very low cutting. By cutting it low (e.g. removing the main growing point) you induce stolonous growth which is how the grass spreads, grow low and forms a thick, close carpet.

Kentucky Bluegrass and Fescue are somewhat different and benefit from a consistent cutting height of 2.5-3.5" consistently throughout the season.

There are much discussion about cutting higher or lower in winter, early spring, summer etc. If you ask a room full of people you will get just as many opinions.

My recommendation is to cut the lawn consistently 2.5-3.5" (height after mowing). During hot summer months you can raise the mower level 1" if you are cutting at the lower end. This to limit evaporation.

Start mowing the lawn when it starts active growth, usually early to mid april and then mow consistently until it stops growing in early november.

For your information:
a cool season lawn should be fertilized in late spring, early fall and late fall (e.g. such as memorial day, labor day, and between halloween/thanksgiving). This is different than a warm season lawn which you would fertilize during summer months. Do not fertilize a cool season lawn during hot summer months. Also, if possible, avoid fertilizing too early in spring (ideal if you can wait until May).