What Does it Mean When Your Mower Misses Streaks of Grass?

Blade Issues and Cleaning

• Blade issues in a lawn mower may be due to trauma caused when the blades hit hard objects like rocks or large branches. However, blades can become less effective without any such force. Blades wear down with each use and require regular sharpening or replacement for top performance. It's also possible the blades are fine, and the streaks are due to debris blocking some of the blades. Clean the mower on a regular basis to prevent those kinds of build-ups.

Which Blades Need Work

• The streaks themselves can determine which blades need attention. If the grass streak is on the right side of the freshly mowed row, start with the blades on the right side of the mower. If the streak is on the left, start with the left-side blades.

Fixing a Bent Blade

• Unplug the mower and the mower's spark plug, which is attached to a wire connected to the engine. Turn the mower onto its side and inspect the blades. If you find a bent blade on the problem side of the mower, use a hammer to gently tap the blade until it is level with the other blades.

Blade Maintenance

• Regular inspection and maintenance helps prevent blade issues. When you sharpen the blades, always place a piece of wood between the blades to prevent the blades from moving. Remove the nut that holds the blade in place to take the blade off the mower. Use any type of file or sharpening stone to sharpen the blade, and return it to the mower. Samuel M. Goldwasser of the University of Pennsylvania recommends a 1/64-inch edge for a mower blade. You can also just replace a dull blade with a new blade.