Quick answer
A sharp blade cuts grass cleanly. A dull blade tears it, leaving ragged, brown tips that lose more water and are more open to disease.
Signs Your Blade Is Dull
- Grass tips look white or brown a day after mowing
- Uneven or ragged cut
- Mower struggles in normal grass
How Often to Sharpen
Many homeowners sharpen once or twice per season. Heavy use, sandy areas, or hitting rocks and roots calls for more frequent sharpening.
Safety
Disconnect the spark plug or battery before removing a blade, and balance the blade after sharpening.