Keep the Blade Sharp . I can spot lawns from the street that have been cut with dull mower blades. Dull blades tear the grass instead of slicing it cleanly. As a result, the frayed tips of torn grass brown quickly and lend an unattractive grayish cast to the freshly mowed lawn.
Torn grass is also more susceptible to disease.
Start the season with a sharp blade and then sharpen it again before the lawn shows any damage. As a general guide, blades need sharpening after 10 hours of use, or at least once during the summer. Also, check the blade regularly for any nicks caused by rocks or sticks. When inspecting the blade, make sure the mower is off and the spark plug has been disconnected. Then wedge a block of wood between the blade and the mower housing to keep the blade from spinning as you loosen the connecting nut.