Your mower blade is probably blunt – here’s how to sharpen it in 5 simple steps

Vonhaus 171cc Petrol Lawn Mower being used on lawn — (Image credit: Future)

As we head into peak mowing season and gardens start growing faster than ever, keeping your lawn mower in top condition becomes far more important. Even the best cordless mowers will struggle to give you a healthy-looking lawn if the blade has become dull over time, leaving your lawn looking uneven and even causing the tips to turn brown in warmer weather.

The good news is that sharpening your mower blade is much easier than many people think, and it can make a huge difference to both cutting performance and the overall health of your lawn. Better still, the same basic advice applies whether you own a cordless mower, a corded electric mower or even a petrol model.

Whilst the removal process may vary slightly depending on the mower design, the sharpening technique itself is largely identical across all three types, and you'll find the exact steps below.

1. Safety first

Before you start anything, the first and most important step is safety. Make sure the mower is completely powered off and remove the battery entirely before doing anything else. You should then put on some protective gloves before moving onto the initial checks.

Once that’s done, tip the mower carefully onto its side (ideally with the air filter and motor side facing upwards) and inspect the blade for any major damage, dents or cracks, as badly damaged blades are usually better replaced than sharpened.

2. Remove the blade

If you've decided the blade just needs sharpening instead of replacing, check your mower's manual to find out how to safely remove it. This usually involves using a socket wrench or spanner, but it will differ with each brand of mower, so make sure you check first.

Once the blade is removed, clean off any built-up grass, mud or debris with a brush or damp cloth so you can clearly see the cutting edge.

3. Time to sharpen

To sharpen it, you can either use a metal file by hand or a drill attachment/bench grinder if you want a quicker option. The key is to follow the blade’s original angle rather than creating a completely new edge.

Work evenly along both cutting edges using smooth strokes, and avoid over-sharpening. This is because mower blades don’t need to be razor sharp like kitchen knives, as a slightly blunt but balanced edge actually holds up better against stones and tougher grass.

After sharpening, it’s also important to check the blade balance by resting the centre hole on a screwdriver or balancing tool. If one side dips lower, file a little more off that side until it sits evenly.

4. Reinstall and retry

After sharpening, simply reinstall the blade securely back onto the mower, making sure it’s fitted the correct way round and tightened properly. Reinsert the battery and give the mower a quick test on a small patch of grass.

A freshly sharpened blade should leave the lawn looking cleaner and healthier, with far fewer torn or ragged grass tips.

5. Stay on top of things

Maintaining your mower's blade depends on how often you mow and whether you regularly hit twigs, stones or tougher terrain. However, as a general rule, they should be sharpened every few months during peak mowing season.

If you plan on staying on top of mowing this summer, I'd strongly recommend sticking to this, especially if you want your mower to last.

Lizzie is T3's Senior Staff Writer, covering the latest in smart home, lifestyle and beauty tech. From skincare gadgets to vacuum cleaners, she's your go-to for trends and top recommendations.

When not writing, Lizzie enjoys mooching around Bath, spending time with loved ones, or testing her review units – often during an enthusiastic cleaning spree!