Rotary mowers are the most common mower for homeowners. It is important to keep the mower blade sharp so the grass blades are cut cleanly. Too often this is overlooked causing the blades to tear and rip instead of being smoothly cut off. Ripping leaves blades open to diseases and stunts the grass. Sharpen the mower blade approximately every 4-6 weeks depending on the size of your lawn. If sharpening the blade yourself, use a file and follow the original bevel of the cutting edge, moving the file towards the cutting edge. Test the blade for balance by placing a screwdriver through the center hole checking to be sure the blade remains horizontal. If not, you may need to remove metal from the non-cutting edge of heavier side until balance is reached.
Reel mowers are not as common and cut grass blades with a scissors-type action. These types of mowers are much more difficult to sharpen at home. Additionally, it is important that the stationary bedknife be properly adjusted to the cutting reel for a proper cut. Check with a hardware store or lawn mower mechanic for proper adjustment and sharpening of reel mowers.