The one-third rule during mowing prevents:

The one-third rule during mowing is a guideline recommending that no more than one-third of the grass blade be removed during each mowing session. By adhering to this rule, scalping of the grass is effectively prevented. Scalping occurs when too much of the grass blade is cut off, which can lead to a range of issues such as stress on the grass, increased exposure to weeds, and even an unsightly lawn appearance. Keeping the grass at a healthier and more appropriate height helps maintain its vigor, encourages deeper rooting, and reduces the likelihood of damage from environmental stresses.

While the one-third rule may also have positive effects on preventing excessive shortness of grass, controlling weed growth, and managing thatch buildup, its primary function is to avoid scalping, thus promoting a more robust lawn.