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
Dave:

As the leaves grow, so do the roots.  You can check the root system by pulling up a few plants.  This is actually a test for golf course type turf, the number of pounds of pressure it takes to remove a swatch of grass.  See if the plant has a decent root system.

You have had rain in Indiana this summer and should have a good stand.

For further root development, I would wait until the leaf growth slows and fertilize lightly.  This should happen when the temperatures are between 40 and 50 degrees F.  Apply 1 to 1.5 lbs of nitrogen per thousand square feet at that time.  The nutrients will go toward root development and be there when weather warms again.

Alternately, you may use a high quality compost which feeds the soil as well as the plants.  It may be found at a professional landscape supplier, should be thermophilically produced (over 131 deg F) and have a nutrient analysis to accompany it.

Hope this helps. Best wishes.