Water is necessary for a healthy, grassy, lawn. However, too much water for long periods of time can be devastating to lawn grass and create prime opportunities for lawn moss to take over. Fix a chronically soggy lawn by increasing sunlight on the lawn, over-seeding the lawn with grass seed, creating drainage pathways around the lawn, and by planting low-level shrubs around the lawn area.
Trim back trees, branches, and limbs that hang over the lawn to allow more sunlight on the lawn area. Increasing sunlight will promote the growth of grass and help to dry out excessive moisture on the lawn.
Over-seed the entire soggy lawn area. Grass absorbs moisture from the soil. By increasing the density of grass on the lawn, more water will be soaked up by the grass roots.
Add lawn lime over the grass seeds. Lime will soak into the topsoil, balancing the pH level and promoting the growth of grass.
Dig a shallow, 3-inch to 6-inch rectangular ditch with a shovel on the uphill side the lawn. Extend the ditch perpendicularly past the edge of the lawn. Fill the ditch with small rocks to facilitate water drainage around the lawn area.
Plant small shrubs around the perimeter of the lawn. The shrubs will soak up water that would otherwise drain into the lawn area.