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Do I Need to Sharpen New Mower Blades?

Credit: Phil Gwinn

Generally, lawn mower blades are ready to use out of the box. The blade will be adequately sharpened for many mowing days ahead. This is especially true if you buy a quality blade. 

However, you should always verify a new blade is sharp and balanced. There are several people, including lawn care professionals,  who claim that they have purchased lawn mower blades that are not sharp and/or balanced.

Either return this type of blade or sharpen and balance it. More on this below. 

Sharpening a Dull Blade

You should be prepared to sharpen and balance your blade when it becomes dull.

Check out our article on lawn mower blade sharpeners. It provides several tool options for homeowners to sharpen their mower blade. 

If you do not feel comfortable using one of these methods, look for hardware or lawn mower repair store near you that will do it for you. To give you an example of the cost, it is $8 for a sharpening at one of our local hardware stores. 

Balancing the Blade

A lawn mower blade balancer is a must have product to determine that each side of the blade is even in weight. If a blade is unbalanced, the heavier side will need to be filled down (sharpened) to match the weight of the other side of the blade. 

An unbalanced blade can create a poor lawn mower performance and an unsatisfactory mow of the grass. 

Some lawn mower balancers to consider are Maxpower Magnetic Wall Mount Blade Balancer or the more economical Stens Blade Balancer

Determine When to Sharpen a Lawn Mower Blade

There are a couple of ways to determine when a mower blade needs sharpening. 

  • Uneven Mow – Take a look at a section of the lawn where the grass has been freshly mowed. If you notice that some areas of the lawn are longer than others, this is a sign that the blade is unbalanced. The blade will need to be sharpened so that both sides of the blade are of equal weight to create balance. Balance can be checked with one of the balancer tools mentioned above or a similar product. 
  • Grass Blade Inspection – Directly after you mow, get down close to the grass blades so that you can inspect them. The tip of the blades that have been freshly cut should not be torn or jagged. Grass blades that are torn are a signal of a dull mower blade. The cut should be clean but not necessarily perfectly straight. 

Why Keep a Lawn Mower Blade Sharp

A dull lawn mower blade will cause the tips of the torn grass blades to turn brown. This will create an undesirable appearance by casting a brownish tint on the lawn.

The lawn will also be more susceptible to disease. Think of it like a cut on the skin. A jagged, harsh cut will be much more difficult to heal and keep away infection compared to a clean, straight cut. 

How Often to Sharpen a Lawn Mower Blade

A mower blade should be sharpened about every 20 hours. This means approximately once a year for homeowners who mow about an hour a week. We like to sharpen at the beginning of the mowing season and mid-season to ensure we have a sharp blade and maintain a quality mow.