Is It Bad to Mow the Grass on a Lawn Too Short? — AKA Scalping 

It’s great to have a beautiful-looking lawn. However, mowing a lawn can take a lot of work, especially if you have a large lawn and use a push lawn mower. To reduce this workload, people often mow the grass very short so that a lawn doesn’t have to be cut as frequently. However, mowing the grass on a lawn too short — aka scalping — is one of the most common mowing mistakes. It’s bad for your lawn to do it. 

Mowing the grass too short (scalping) is bad for your lawn

Mowing the grass at the proper height is one of the best ways to have a healthy and beautiful lawn. It helps enable sunlight and essential nutrients to penetrate the grass. Grass cut at the proper height also helps keep weeds and disease at bay.

Conversely, mowing the grass too short is bad for your lawn. Scalping damages a lawn in multiple ways, as detailed by Lawn Doctor. This includes:

• It restricts the nutrient supply to the grass. To grow and survive, grass uses photosynthesis, which is the process of taking in sunlight and using it as energy. Scalping the leaf blades “limits the lawn’s ability to store this energy, restricting its nutrient supply and ultimately choking the grass.”
• Cutting the grass too short is especially damaging in hot and dry weather. Longer blades of grass lock in moisture, while grass cut too short is more susceptible to the stresses of drought. 
• Scalping a lawn can damage the crowns of the grass plants. Along with inhibiting the growth of the grass plant, a damaged crown can lead to other problems. As the crown diverts its energy into recovering from the damage, a lawn is less able to fight off weeds, insects, and diseases. 

Dull lawnmower blades worsen the negative effects of scalping

Something that worsens the negative effects of scalping a lawn is dull lawn mower blades. Mowing a lawn with dull blades can result in torn and frayed grass. If your lawn looks torn and frayed, you’ll need to sharpen the lawnmower blades. A blade sharpener can be purchased at a home and garden store.

What is the best height to cut the grass?

The ideal height to cut the grass on a lawn varies for each grass species. However, generally, during the growing season, the best height to cut the grass on your lawn is around 3 inches. The minimum mowing height to avoid scalping and damaging a lawn is 2 ½ inches. There are exceptions, though, such as bermudagrass, which can be cut at a height of 1 to 2 inches. But for the grass varieties that are common for most lawns, around 3 inches is the recommended height. 

Mowing at the proper height will help create a healthy and beautiful lawn — and one that doesn’t need to rely on chemicals. Cutting the grass at around 3 inches typically translates to a mowing frequency of around once per week — or less during hot and dry periods.

Also, a general rule to follow is to never mow more than the top third of the blades of grass during a single mowing. Additionally, it’s best to leave the grass clippings on the lawn following a mowing. Through a process called “grass-cycling,” the clipped grass will decompose and return vital nutrients to the soil, aiding the health and growth of the grass plants.