What Happens If You Mow Your Lawn With Dull Mower Blades?

Struggling to achieve a cleanly cut lawn? You probably need to sharpen your lawn mower blades.


In this short guide, we’ve shared what will happen to your lawn if you mow with dull blades. We’ve also offered advice on how to know if your lawn mower blades are dull, and how to fix dull blades at home.

✅Key Takeaways:

  • Mowing your lawn with dull lawnmower blades will shred the tips of your grass rather than cutting them cleanly.

  • This gives grass blades jagged, brown edges and makes them more susceptible to disease.

  • You can resolve a problem with dull lawnmower blades by sharpening the blades with a special sharpening tool.

Table of Contents

✂️ Effects Of Dull Mower Blades On Your Lawn

Dull blades on your mower will produce a raggedy cut that may cause the tips of your grass to turn brown. The grass blades are also more susceptible to disease when cut with a dull blade.


To understand the effects of mowing with dull lawn mower blades, we need to clarify why a sharp blade is necessary.


Mowing grass with a sharp mower blade provides a clean cut, meaning that the grass ends are snipped evenly, rather than torn.


When grass is cut cleanly, it recovers more quickly after cutting. It should grow more healthily and with a lower risk of disease. Healthy grass also chokes out invasive grasses and weeds, giving you a greener, consistent lawn that’s easier to mow, putting the engine under less strain.


Mowing grass with dull blades shouldn’t have disastrous effects, but if you want to enjoy a healthy lawn year-round, we recommend that you sharpen dull blades whenever you notice them.

poor, cut, quality, grass, cut, lawn,

Poor quality of cut

Good, cut, quality, grass, turf,

Good quality of cut

🔨 How To Know If Your Mower Blades Are Dull

You’ll know if your lawnmower blade is dull by conducting a visual inspection.


A dull mower blade will have bends, dents, and nicks. If you carefully touch the blade, you’ll notice that it feels blunt and thick, with no sharp edge.


You can also identify a dull blade by checking the quality of your grass after mowing. If the grass is uneven and has jagged edges, or your grass turns brown a few days after being cut, you likely have a dull blade on your mower.

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🤷‍♂️ What To Do About A Dull Mower Blade

The simple solution to a dull lawn mower blade is to sharpen the blade.


You don’t need to send your lawn mower to a specialist to get your blades sharpened, and, nine times out of ten, you won’t need to invest in new mower blades Simply sharpen the blades at home with a special sharpening tool.


Don’t have a blade sharpener in your shed? There are several tools you can use, including a bench grinder, a metal file, or a hand grinder.


We recommend the SHARPAL 103N All-in-1 Knife and Garden Tool Blade Sharpener, a popular sharpening tool for UK gardeners. You can use it to sharpen your lawn mower blade as well as secateurs, shears, axes, scissors, pruners, and kitchen knives, so it’s a good versatile tool to have on hand.


We’ve shared a simple step-by-step process on sharpening a mower blade in this guide on how to sharpen a lawn mower blade.


If the mower blade is bent or damaged, skip the sharpening and buy a new blade.


A new blade can significantly improve the quality of grass cut with a ride-on or push mower. You can buy a new blade direct from the manufacturer or from online marketplaces like Amazon for around £10-£15.

changing, mower, blade,

🪒 Should A Lawn Mower Blade Be Razor Sharp?

A lawnmower blade shouldn’t be razor sharp. If the blade is too sharp and thin, it’s more likely to chip or dent if it hits something while spinning at high speeds.


The edge of your mower’s blade should be about as thin as, and a bit sharper than, a butter knife. No need to make the blade any sharper.

🏁 Final Word

Blades are one of the most essential mower components to maintain if you want to enjoy a healthy lawn and put less stress on your grass.


Dull lawn mower blades can’t cleanly cut your lawn. They’ll shred the ends off each grass blade and make your mowing job harder because the blades are less capable of quickly snipping your grass. This will cause your mower’s engine or motor to work harder, putting it at risk of burnout.


The simple solution is to sharpen your blades at least once or twice per mowing season. At the start of the season, flip the mower on its side, giving you access to the mower deck. If the blade’s condition is poor, sharpen it before you start mowing. Make sure you have a suitable sharpening tool for the job.