St. Augustine grass is a popular warm-season grass known for its ability to survive shady environments that receive as few as four to six hours of sunlight daily. St. Augustine grass is drought resistant and tolerates moderate wear and tear. Unfortunately, some gardeners have difficulties getting St. Augustine grass to spread. Thick thatch layers, infertile soil and soil compaction are underlying causes for grass problems. By addressing these underlying issues and applying fertilizer properly, most gardeners can enjoy a thick St. Augustine turf.
Press a measuring stick through the St. Augustine grass blades to the soil to measure the thatch layer. Thatch is the layer of dead and living organic material that accumulates between the soil and grass. A thatch layer over a half-inch deep prevents St. Augustine grass from properly spreading. Because St. Augustine grass produces a moderate thatch amount, it is likely there is too much thatch between the soil and grass.
Push a power dethatcher back and forth across existing St. Augustine grass to remove the thatch. A power dethatcher used its blades to rip thatch through the grass blades. Gardeners should dethatch when the grass is actively growing, so that the lawn can quickly recover. Rent a power dethatcher from a local gardening center.
Rake up the St. Augustine thatch debris from the top of the lawn and dispose of it. Aerate the St. Augustine lawn with a core aerator. Core aerators dig up small plugs of soil up to 3/4-inch wide and 1 to 6 inches deep. By aerating the lawn, gardeners increase soil drainage and fix soil compaction. Rake up the plugs of soil.
Fertilize St. Augustine grass with nitrogen slow-release fertilizer when the lawn greens up in the spring. The timing depends on your climate, but the grass should be 50 percent green before fertilizing. Pour half of the amount of fertilizer granules you want to use in a drop spreader. Push the drop spreader evenly across the lawn. Add the rest of the fertilizer and push the drop spreader at a 90-degree angle to the first application to achieve even coverage.
Water the lawn to help the soil absorb the fertilizer. Fertilize again in six weeks.