What Causes Ruts in a Lawn?

Mowing Patterns

Mowing the grass using the same pattern constantly over time creates ruts in the lawn. As the lawn mower tires move over the same piece of ground each time they begin to compact the soil. As the soil is compacted in a single location it forms a depression in the ground, causing a rut.

Grass should be mowed when dry. When grass is wet, the soil supporting it is also wet. Wet soil compacts faster than dry soil because the weight pressed against it pushes out moisture. As moisture leaves, the ground compacts to close the gaps left by escaping moisture.

Sloping ground or hillside lawns have an additional problem with erosion. The Guliford County Environmental Health Department describes erosion as the natural process of wearing down any surface. The agency further states that "most erosion occurs when concentrated water flows over unvegetated surfaces." Unrestricted water flow, or runoff from hills, can cause ruts in the lawn as they continuously follow specific routes down the slope. While grass may be present, these routes eventually become visible as the water drowns roots, causing bare spots and settling.

Rodents such as voles move underground through tunnels. Voles eat plant roots exposed by the tunnels they dig. As the roots are eaten, the plants die leaving exposed soil. As the tunnels are developed, the weight of the surface soil compacts, forming ruts on top of the tunnels.

Using alternating mowing patterns where the pattern mows against the grain of the previous pattern eliminates the potential for compaction. Look for droplets on grass blades; if you find them the grass is too wet to mow. Feel the grass; if your hand is wet wait. Vector control in the form of natural predators such as cats and hawks help control voles and other rodents. Creating alternate drainage paths for water prevents the water from traveling unwanted routes. French drains constructed along the side of the hill help drain runoff. Planting trees such as willows at the top of the hill controls runoff through soil retention and taking up excess water.