There is no need to dethatch your lawn before seeding. In fact, you may actually do more harm than good if you try to dethatch an established lawn. Dethatching can disrupt the turfgrass plants' root system and damage the turfgrass canopy. This can lead to erosion, weed competition, and a decline in the overall health of your lawn. If you do decide to dethatch your lawn, be sure to only do so when the grass is actively growing (early spring or late summer) and use a hand rake or power rake instead of a mechanical dethatcher.

It depends. If the layer of thatch is more than 1/2 inch thick, then yes, you should dethatch it before seeding. A thick layer of thatch can inhibit water and air penetration to the soil, making it difficult for new grass seedlings to take root. If the layer of thatch is less than 1/2 inch thick, then you probably don't need to dethatch it before seeding. You can test to see if your lawn needs dethatching by using a garden rake. Run the rake over the lawn in several different directions; if the rake pulls up a lot of dead grass and leaves behind a thin layer of live grass, then your lawn does not need deth