How Low Should I Cut My Grass?

People often do not think twice about how low they cut their grass, either they pick the lowest setting or whatever is most convenient. But how low you cut your grass can significantly impact the health of your lawn, especially with certain grasses.

Grass, like most plants, can be pruned only so much at one time without impacting its natural growth rhythms. The magic amount is about 1/3rd of the grass’s height. No matter how tall your grass grows, you should not cut more than 33% of it on any given day. If you cut too much at one time, the plant can go into a state of shock impeding growth and development.

This might not seem so bad; the grass doesn’t grow as fast and needs cut less which might sound like good thing. But there are four big consequences:

  1. The roots go into a state of shock and get weaker. This makes it harder for the grass to remain the dominant plant in the yard and weeds can get a strong foot hold and start to take over.
  2. Some of the grass will die. Rarely is it a large patch, but rather a small percentage sprinkled throughout. So if a small percentage of your grass dies each time, and the grass isn’t strong enough to suppress weeds anymore, then your lawn can be taken over by weeds, insects, and even disease.
  3. The weakened grass will be less resistant to heat, drought, disease, insects, etc. Which means even more grass will die and even more problems will move into your lawn.
  4. Clumping. The more you cut in one pass the more volume of grass is created and the higher the chances of the grass clumping up when it comes out of the mower. Dealing with clumps takes time and energy, either you have to bag it, mow twice, or rake it up. At best, clumping looks bad suck up time to fix. At worst it kills patches of grass and creates a hub for disease and pests if left unattended.

You may see lawns that should be healthier, should have less weeds, and should be more heat resistant, but for seemingly no reason the lawn is always doing poorly. The reason is often that the grass is cut too low.

On the other side, you may see lawns where the grass always looks good, is strong and vibrant all year but it doesn’t look like the grass gets much special treatment. The reason may simply be it is not over cut.

This is why lawn care providers recommend weekly cuts and often caution against cutting less regularly.

So do not wait until your grass is high to mow it, even if you are only taking off 20%, that is key to a stronger, healthier lawn.