Mowing height is the most important aspect to mowing. Mowing height can affect the appearance of any lawn no matter what it's condition is. Cool season grasses (Bluegrass and Fescue) can be affected by mowing height more than warm season grasses (Zoysia and Bermuda). Cool season grasses do not tolerate being mowed short very well. Only in the spring and fall will they tolerate it. Cool season grasses grow best when cut tall, in fact, as high as your mower will go. We have never seen a mower that cuts too tall! Most people say to cut cool season grasses between 2 1/2" and 3" high. Well, who knows how many inches a mower cuts? Forget about inches. After the first mowing of the year, SET THE MOWER AS HIGH AS IT WILL GO! This is the main thing we stress here at Tobin Lawn. Too many homeowners think their lawn should look like a golf course, and they cut too short. First of all, they don't have the time and resources a golf course does. So it's not going to respond like a golf course. Grass grows better when it is cut taller. Period. The higher grass is cut, the deeper the roots will grow. Mowing short reduces vigor by reducing the plants ability to manufacture food. The grass will thin, weeds will invade and the roots will be shallow. Mow TALL!