I am in the piedmont also, what a lot of people refer to as zone 7 but I don't believe in zones so I don't use them myself but the temps you mention are similar to here. I would never get to raise the height much because come september when the temperature plummets so does the growth rate of this grass and even with fertilizer I haven't been able to get a significant increase in height after cutting it short for the whole season. Nothing major bad has happened to it. Lost a little bit last year but it wasn't a big deal bad might have actually been from a late freeze. In this area, this is when the optimal growing time for Bermuda comes to an end. It will slow down and lighten up and the zig zag marks come next month then it's all over. So I hope you enjoyed it while it lasted.

You've got what the social scientists call a 'special situation'........which is Greek for 'Hey, we don't know'. You can't figure this out. Not without experimenting. You have to turn your lawn into an experiment, and specifically, mow, over a WHOLE season (May will have different results than August will...) a strip of lawn at 2", the next strip of lawn at 2.5", and the next strip of lawn at 3". Repeat. Forever. See sketch. You will be able to tell, over the course of the season, which height works better, or you will be able to tell that no height works better, and in fact things are what they are. Then, you have to deal with the 'audience'. Whether spouse, neighbors, older kids, whatever, you will in fact have peeps asking 'what's with the uneven lawn, back there?'.....you will have to develop a thoughtful, superior, scholarly, look about you, and explain, vaguely, that you are determining which lawn height works best, in the real world, with kid traffic. Because there's a Lawn Forum, on the internet, and yes, you are hard wired into the internet, and all these cutting-edge people (and if WE aren't 'cutting edge' [lawns. mowers. trimming. Never mind.], who is?) need you to figure this out for the betterment of mankind, etc. You will then have to get a patio chair, and a side table (placed next to the chair). Perhaps a book on the table, perhaps not. You will then be able to enjoy evenings, sitting in the chair, occasionally contemplating, studying, the course of your experiment. You will be discussed: 'Do you know what Jon's doing?'.....the audience will BRING you refills, as you sit there. They will offer advice. You will, of course, say 'Hmmmmmmmm'. Life is good.

Central MA is Zone 10? Don't you think it's more like Zone 6? From K-State Extension where I volunteer and from my turfgrass prof in college -- mow it short the last time you mow -- about two inches. You might want to check with UMASS Extension to see what specific height they recommend for your area, but I suspect it will be about 2". The objective is to not have grass so tall that it mats down under snow cover and develops snow mold.

To me, that's not a reason to scalp before overseeding. I scalp to reduce competition to seedlings from established grass - scalping stunts growth and prolongs the time until the first mowing. It also helps with seed to soil contact. If lowering the canopy doesn't open the soil surface up to sunlight (and consequently, seed finding its way to the soil as there is less canopy to block the seed during overseeding), what is the existing turf out-competing the seedlings for that you are reducing by "scalping"? BTW, I am not talking "scalping". We are talking marginal, yet significant reduction of the canopy to open up access to the soil. If mowing down to 2-2 1/2 inches doesn't reveal access to the soil, then the lawn is already as thick as it is ever likely to be and neither overseeding nor promoting spreading are necessary, likely to be effect, or desirable.