Question
I reseeded my backyard this summer. It is doing really well.
My question is :  In order to get the root system as well established as possible before winter, is it best to just let it grow as long as possible before mowing? Or is it best to keep it mowed short? The type of grass is Tall Fescue, with a bit of Bluegrass and Perennial Ryegrass mixed in. My goal is to get the root system well-established before winter sets in. I am located in Northern Indiana.
Thanks, Dave

Answer
Mow twice a week at this time of year, but set the mower at 3 inches.  The roots will grow longer and deeper -- Fescue especially grows down so far you could drill oil with it.  Don't forget to water DEEEEEEEP.  Not long, not regularly, just DEEEEEEEEEP.  A top dressing of Bonemeal will get the Phosphorus down where they need it, released slow and steady.  Nice work.  You sound like someone who knows what they're doing.