How to Tell if Mower Blade is Dull in 8 Simple Ways

Mowing your lawn is not a hassle-free task, particularly with a dull mower and can’t tell. There is a difference in how your lawn looks when you cut with a sharp or dull blade.

Using a sharp mower blade makes the lawn look manicured, neat, and even healthy. It is the reason why it’s always recommended to use your mower with a sharp blade. Before mowing your lawn, check the grass tips to know the condition of the mower blade.

A dull lawn mower blade will even pull up portions of grass or the entire plant instead of slicing. That’s the same way as cutting a good steak with both a sharp and dull knife.

Let’s explore how to tell if mower blade is dull.

How to Tell if Mower Blade is Dull

There are various ways to compare a sharp and dull mower blade. A dull mower will need sharpening before you continue using it on your lawn. Here are signs that your lawn mower blade needs sharpening:

1. Uneven Grass Height

Experiencing an uneven grass height is something common. However, suppose you realize there is a continuous uneven level of the grass height. In that case, it means the mower blade is dull and requires sharpening.

Sometimes, that may not be the cause of uneven grass. Try to align and tighten the blade. If it doesn’t work, you can conclude the blade is dull.

2. Mowing an Area Multiple Times

If you are using a dull mower blade, it forces you to pass one area several times to get desired grass height. When that continues to happen routinely, it’s an obvious indication that the mower blade is dull. You may have to replace the blade or sharpen it.

3. Taking Long to Mow

Sometimes, long mow times will not mean your blade is out of shape. The reason could be your mower doesn’t move swiftly through the grass. Ensure your mower moves swiftly to determine whether the blade needs sharpening.

4. Push the Mower Hard

If you have a walk-behind or push mower, dull blades will make simple lawn care a full-blown workout. When the lawn becomes strenuous, the mower blades are dull and require sharpening.

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5. Torn Grass

A sharp mower blade will give you an even grass cut. With a dull blade, your lawn will not look clean. It means the mower blade is dull when you realize you have many torn grass instead of well sliced.

how to tell if your lawn mower blade needs sharpening

6. Dented or Bent

Sometimes, you can tell your mower blade has an issue by looking at the blade itself. Over time, blades will get dull and damaged. So, with sizeable dents or having a bent requires you to sharpen or replace it.

7. Frequent Stalling

Many issues will make the lawn mower stall. One of the reasons is having a dull blade, thus forcing the engine to overwork. When your mower stall while mowing thick areas, it means the blade is dull and requires sharpening.

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8. Blade Pulling up Dirt or Chucks of Grass

A sharp mower blade should cleanly slice through the grass. With a dull mower blade, it will pull clumps of grass and some dirt as well. A sharp blade will not pull the grass but slice it.

Also: Prevent grass build up on top of mower deck 

You need to sharpen your mower blade at least 2 – 4 times a year. If possible, do it after every 8 mowings. Remember, mowing may not need an overly sharp blade – although sharper than your butter knife.

Remove the blade carefully from your mower and sharpen it with a grinder. And if you don’t feel comfortable sharpening the blade yourself, ask for a retailer to sharpen it for you. The reason is that the blade will also need balancing.

To sharpen the blade yourself, ensure you have balanced the lawn mower blade before attaching it back. After working, also wash it and keep it clean and dry to extend its life.

It is recommended you always check your mower blades at the start of the mowing season. Look closely for bends, dents, nicks, or damages to the blade to take necessary measures.

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Why Use a Sharp Mower Blade?

Mowing using a sharp blade creates a straight, clean cut. When you have clean-cut grass, it can recover fast, thus fighting off chances of any disease. With healthy grass, it will choke out an invasive and pesky weed.

In addition, while mowing, it will be easier because the grass will grow easily, saving your engine.

Grass catcher for Zero turn mower

FAQ: How to Tell If Mower Blade Is Dull

When do I know it’s time to replace my lawn mower blades?

The lawn should look uneven after you mow one pass rather than clean. That means the mower blades are dull and require replacing.
Another way is to check the grass blades; you can change the mower blade when you find them torn and not properly sliced.

What happens with a dull mower blade?

Dull lawn mower blades will lead to lawn disease, pulling portions of grass while mowing, lawn discoloration, ragged-looking grass, or plant dies. If you cut the grass cleanly, it will recover easily, thus reducing the risks of diseases.

Should I sharpen or replace the dull mower blade?

A lawn mower blade is built for durability but salvaged with regular sharpening. However, replace the blade to avoid breakage when it has large dents or chips on the edge that you can’t smoothen with a sharpener.

To achieve a healthy and great lawn, you must sharpen your lawn mower blade regularly.

The right time for sharpening could be at the start and in the middle of your mowing season; when the mower picks stray debris during the mowing season, schedule for additional sharpening when needed.

Importantly, know how to tell if mower blade is dull or not. You can check the above tell-tale signs for identifying a dull mower blade.

Also, make your sharpening time depending on workload to stay on schedule. The tricks will help you have a trained eye to keep your blade up to par.


  • Ricky

    Hi, I’m Ricky. I’ve been involved in lawn care and landscaping from when I was 15. To be honest, I didn’t like the idea of pushing mowers, collecting grass clippings, and maintaining flowerbeds at the time. But having seem the passion my parents had for gardening and outdoors and the effort they put in maintaining the health and beauty of our landscape, I couldn’t help but not only admire their hard work but also I became a part of it. As someone who loves to spend time with nature’s best, I find myself learning a lot more about gardening and outdoors on a daily basis. Not to mention I love to share the knowledge I’ve gathered over the years with my readers at We Mow Dallas. To be clear, I don’t have a Master’s degree in gardening or anything like that. Everything I’ve learned about gardening, landscaping, and lawn care spring from passion and engagement with my parents. And with a ton of free information out there, plus the ability to run tests and determine what works best for lawn care and landscaping, every day is an opportunity to learn and implement something new. My goal with We Mow Dallas is to teach you exactly how to maintain your lawn and landscape. And since I walk the talk in reality, you shouldn’t hesitate to join me in this wonderful world of landscaping and lawn care. K Beatrice

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