Mowing height is the key to keeping grass uniform and attractive.
Most lawns are a mix of Kentucky bluegrass and fine leaved-fescue.
You should mow this type of lawn two an one-half to three inches above the soil line. Grass cut to this height shades the soil, and helps keep weeds from establishing themselves. This shade also keeps the soil temperature cooler. The higher you mow your lawn, the less frequently you need to do it. Mowing the grass shorter may make it more susceptible to injury from drought and disease.