Over time dead grass and debris build up on the surface of your lawn and become embedded on top of the soil. This layer of debris is called the thatch layer. When the thatch layer becomes too thick all of the nutrients that the grass needs aren’t able to get to the roots. The grass will become starved and begin to thin and die. It also promotes fungus growth and pest infestation.Do I need dethatching? You can test your thatch layer by digging up a small shovel full of your grass.After digging it up you can inspect the sample for the thickness of the thatch layer.If the thatch layer is thicker than 1/2in then you needed dethatching.How do I dethatch? You can use a power rake, hard tine rake, or a special dethatching rake and give your entire lawn a once over and dispose of the debris.You’ll need to ensure that your rake is penetrating the thatch layer but not the soil.How can I avoid dethatching? Aerate. Lawns that are regularly aerated don’t need dethatching. Aeration reduces compaction, makes the ground more even, manages the thatch layer and allows water, air, and nutrients to penetrate the roots of the grass. This encourages new stronger root development and increases density in the lawn.