A new lawn should be mowed as soon as it reaches regular mowing height. The mower should be sharp because a dull blade might rip young seedlings out of the soil. Then regular mowing, usually 7 to 14 days, during the growing season is the main task in maintaining a lawn. If the wheel tracks are still visible from the last mowing, then it is a good idea to vary the mowing pattern. I mow north and south one week, then east-west. This prevents ruts from running the mower wheels in the same track each time.
Mowing height is measured from the mower blade to the ground with the mower sitting on a flat surface. Mowing height for most grasses is 1.5 to 2 inches. For the summer, a mowing height of 2.5 to 3.5 inches will reduce water and fertilizer needs. Mowing at 1.5-2 inches during the rainy season reduces disease problems. Grass should be mowed as soon as it reaches one and a half times mowing height so only one third of the grass height it mowed off. If grass is allowed to get tall, then cut short, the soft, lush base of the grass will be exposed to hot sun and it will burn and turn brown. If the lawn gets too tall, set the mowing height higher, then, a few days later, mow the lawn again at the regular height. This is especially important during hot weather.
Mulching the clippings back into the lawn builds up the soil and requires less fertilizer, but if the grass is tall or wet, the clippings may pile up and smother the grass.