How Mowing Affects Roots

Grass Height

• The higher the plant, the better the ability to shade out competing plants-- and weeds and grass are in a constant battle for height supremacy. Mowing under 3 inches allows weeds to grow over grass, shading grass and depriving it of sunlight. Maintaining a mowing height of 3 inches allows grass to remain above weed seedlings and propagate, forming thicker turf to further crowd out weeds. Mowing lower requires more maintenance and management, but higher grass generates more nutrients for roots to grow deeper into the soil. Deep roots, in turn, take advantage of nutrients and moisture deeper in the soil, thus creating healthier blades of grass. Deep roots are also more resistant to disease.

Mowing Frequency

• Mowing often is important to maintaining thick turf. Mowing too often, however, scalps grass, forcing the plants to continuously produce blades to produce sugar for the roots. The roots must then remain small and near the surface to sustain the plants. Grass maintained around 3 inches has a slower growth rate and requires less-frequent mowing.

Lawn Mowers

• Mowing with damaged or dull blades causes ripped or torn blades of grass, which exposes grass to disease that can affect and kill roots as the plant tries to repair the blades of grass. Keep your mower blades sharp to make clean cuts that the plant can adapt to faster. Frequent cutting with sharp blades reduces plant stress and forces thicker root and grass-blade growth.

Moisture

• Use less water when you keep higher grass and deeper roots. Higher grass creates more shade on the soil, requiring less watering. Deep roots use the moisture within the soil and therefore need less watering. Mowing when the grass is still wet--that is, when there are water droplets on the blades--compacts the soil because of the weight of the mower. Compacted soil loses oxygen, and in turn the roots suffocate, causing brown patches in the lawn.

Recycling Grass Clippings

• Mowing with mulching blades chops grass into small, short pieces. These pieces return to the soil as compost rich in nutrients, which the roots use as food.