A thatching rake is used to pull dead and compacted plant material from between the blades of actively growing grass. Compacted thatch prevents air and moisture from getting into the soil and slows new grass growth. Also, the decaying plant matter may cause fungal and mildew diseases in the lawn. It is best to dethatch your lawn when the grass is actively growing, so you don't damage emerging grass or pull up live grass sections or rhizomes while you are working. For best results, dethatch regularly so thatch remains below 1/2 inch thick.
Choose a day in the fall when the grass is still actively growing and you will probably mow another two or three times. By choosing a period in the fall you can remove the thatch that has accumulated over the summer so it does not become impacted over the winter.
Put the blades of the thatching rake into the lawn and pull the rake toward you, removing the dead organic matter or thatch from between the grass blades. If the grass is healthy, you should be able to pull up the thatch without damaging the growing grass. It is okay if some of the grass is damaged; however, you don't want to pull up a large part of the green lawn.
Use a leaf rake to rake up the thatch that you loosened with the thatching rake and place the loosened thatch in a wheelbarrow. Place the thatch in the mulch pile only if there are no herbicides present in the lawn grass because some herbicides, such as those present in weed-and-feed products, can remain viable in the organic matter even after it is composted.