Why Is My Lawn Mower Cutting Unevenly? And How Do I Fix It? A freshly mowed lawn should look tidy, healthy and consistent. However, damage or malfunctioning parts on your mower can leave you with patches of long grass, or worse, a scalped lawn. Finding areas of uneven grass when you’ve finished mowing can be frustrating, but don’t worry, the issue can usually be resolved with general maintenance and adjustment to your mower In this article, we cover why your mower isn’t cutting your lawn evenly, and how to fix it to get that clean, professional finish. Signs Your Lawn Mower Is Cutting Unevenly Before getting into the causes of uneven cutting, let’s quickly review the symptoms. Common signs include: Stripes of grass that look longer than the rest of the lawn Patchiness once you’ve finished cutting Scalped areas where the grass has been cut too short Ragged or torn grass blades Having to repeatedly pass over the same area If you’re noticing any of these issues, one of the following causes is likely responsible. 1. Dull or Damaged Blades A blunt, bent or broken blade is one of the most common causes of uneven cutting, and due to getting a lot of use, blades will naturally become dull over time. A sharp blade slices through the grass cleanly, whereas a dull blade will tear and rip the grass. As a result, patches of your lawn will appear ragged and uneven. How to fix it: Visually inspect your blade regularly and look for: Dull cutting edges Chips or dents Bends in the blade from hitting stones/large roots If your blade has simply gone blunt, you just need to sharpen it. If it’s damaged beyond repair, replacement is always recommended. As a general rule, you should sharpen your blades at least once a season, or every 20–25 hours of use. 2. Incorrect Lawn Mower Cutting Height Ok, this one may seem obvious, but believe us, it’s a common issue. If your mower’s wheels are set to different heights, then the lawn deck will be uneven. As a result, you’ll get patches of unevenly cut grass. How to fix: Double-check all your mower’s height adjustments to ensure they are all in the same position. On some lawn mowers, you can adjust each wheel height individually, so make sure they’re equal before you start mowing. Test out your adjustments on a flat area of grass and see if the cutting quality has improved. 3. Mower Deck Not Levelled Speaking of mower decks, if yours is out of alignment or tilted, one side will obviously cut lower than the other. You’re more likely to experience this problem with ride-on lawn mowers and garden tractors. How to fix: Leave your mower parked on a level surface and measure the gap between the deck and ground on both sides. If one side is higher than the other: Refer to your manufacturer’s instructions for deck adjustment Tighten any loose screws or mounting brackets Continue making adjustments until your deck is level on both sides A level deck can make a big difference to your mower’s cutting quality. 4. Improper Tyre Pressure This problem is specific to ride-on lawn mowers. If one tyre isn’t fully inflated, your mower may sink down on that side causing the opposite side to cut higher. How to fix: Use a pressure gauge to check the air pressure on all tyres, and inflate them to your manufacturer’s recommended PSI, making sure the pressure is even on both sides of the mower. You’d be surprised how many people overlook this quick check, and it often solves uneven cutting issues right away. 5. Blocked or Dirty Mower Deck Every time you cut your lawn, grass clippings, mud and debris accumulate on the underside of your mower deck. Leaving it to build-up will restrict airflow and stop the blade from cutting grass properly. How to fix: After every use: Disconnect your spark plug or power source Tip your mower (according to the manufacturers instructions) Remove any grass clipping build-up and other debris Wipe down the underneath of your mower deck A clean mower deck is vital for optimal cutting performance and longevity. 6. Slopes and Improper Mowing Technique Your mower might be perfectly fine, and instead the cause could be your lawn. Bumps, hills and uneven surfaces are difficult to mow across, especially with a walk-behind mower, and mowing too fast can also cause uneven cutting. how to fix: Take your time and you’ll notice an improvement. Make sure you: Slow down Overlap your lawn mowing passes Alternate directions Mow across slopes instead of up and down Raise your blade height when cutting over bumps These tips should help prevent scalping and produce a more professional finish. 7. Bent Wheels and General Wear and Tear If your mower has damaged wheels, a bent crankshaft or any other structural issues, it will be very difficult to get an even cut. Any damage to your mower can affect the balance of the machine and blade orientation. How to fix it: Closely inspect your mower for: Worn wheels Damaged or loose wheel assemblies Vibration when idle Any bent parts or blade shaft damage If you suspect your mower has serious damage, you may want to take it to a certified technician. How To Prevent Your Lawn Mower From Cutting Unevenly The best way to avoid uneven cutting is through regular maintenance. A few simple habits can keep your mower performing at its best: Keep your blades sharp Clean your mower deck after every use Check your tyre pressures regularly Ensure your wheels and cutting height are even Avoid cutting wet grass Get your mower serviced annually Conclusion You don’t need to replace your lawn mower if it’s leaving you with an uneven finish. 9 times out of 10, it’s caused by dull blades, uneven cutting heights, tyre pressure, deck levelling issues or general maintenance. If your machine regularly breaks down, replacement parts are becoming difficult to find, or repairs are costing more than the mower is worth, it may be time to upgrade. Check out Mowshops range of lawn mowers and garden machinery. We offer everything you need to achieve a professional cut at home.
