Lawn dethaching is when you rake the lawn to remove the dead thatch from the lawn. A thick layer of thatch can harbor disease-causing insects and fungi, prolong high humidity that promotes disease, and bind or tie up pesticides. And as thatch builds, grass roots knit into the thatch layer instead of the soil, where they easily succumb to environmental stresses such as prolonged periods of hot, dry weather. We raked that sodded lawn 4 different ways to remove as much thatch as we could. Too much thatch is not good for a lawn.