When To Sharpen or Replace Your Mower Blade(s)

One of the most important tips to having a healthy lawn is to use sharp mower blades. Sharp blades cut grass cleanly which helps the grass to recover faster and stay green. A dull blade will rip the grass blades, leaving ragged tears that weaken the grass and promote grass diseases. Mowing with sharp blades will also reduce your mowing time.

Typically, most home owners just need to sharpen blades twice per season. One good sharpening at the beginning of the season and one around the middle of the mowing season should be good. If you mow over debris such as sticks or rocks, however, you may need to sharpen your blades more than that. There are a few things you can watch for to determine if your mower blades need sharpening.

1. The first thing to watch for is unevenness in your lawn. Your grass should be cut at the same height with one pass of the mower. If your lawn looks uneven after mowing one pass all the way around then your blades are probably dull.
2. Another way to determine if it’s time to sharpen your blades is to inspect the grass blades. If the tips of the grass blades are torn and not cleanly-sliced, it’s probably time for a sharpening. Torn grass tips can impact grass health, causing the grass to turn brown.
3. Finally, you can also inspect the blade itself. Look for large chips or dents in the cutting edge. Inconsistencies in the blade are likely to tear grass rather than give you an even cut. Also check the thickness of your lawn mower blade. Over time, dirt, sand, and other debris can erode the blade, causing the metal to weaken and become paper-thin. If you see this, you should replace the blade immediately since it can break while mowing and possibly injure someone. We have included some photos to help you determine if it is time to replace your blades.

The trailing edge, or fin, is the edge opposite the cutting edge. In this photo you can see the blade has become thin. When it’s thin, it’s time to replace the blade.

Check to see if your blade is bent. If you’re not sure, compare it with a new blade.

Look for dents or cracks in the cutting edge. Be sure to replace any blade that has any dents or cracks so the blade does not break apart during mowing, fly off and hit someone.

If you need your mower blades sharpened we can help. Just bring in your blade(s) to any one of our five Minnesota Equipment store locations. If you are not sure if you need to replace a blade just bring it in and we can with that as well. We have many blades in stock if you need a replacement.