The Theory Behind Power Raking
In the spring, a new growth cycle begins with the emergence of new blades of grass. During the fall, blades of grass that were once a beautiful shade of green flop over and die. Over a period of a few winters, a considerable amount of dead grass or thatch can accumulate. Power raking simply removes the top layers of this thatch.
While people often use the words thatch and mulch interchangeably, they really are two different things. Mulch is different from thatch in that it is a compost of live grass that has been cut. Mulch is extremely beneficial to the lawn because it recycles the nutrients that are in the grass back into the soil and the enzymes in the mulch also help with breaking down the thatch. Whether you bag, mulch, or side discharge your lawn clippings, thatch buildup will occur. A small layer of thatch is beneficial because it helps keep the soil cooler which in turn causes less water evaporation. However, a big layer of thatch is bad because it actually smothers the new grass from growing.
Power raking is designed to remove the excess layers of thatch on top while maintaining the protective layers on the bottom. Because of our climate, excessive thatch build up is not as big of a concern as it is in other parts of the nation. Depending on your lawn mowing and lawn maintenance habits, power raking ever 3-5 years should be adequate. Side discharge mowers tend to increase the amount of grass because it blows out large clumps of grass, whereas, mulching mowers actually help with thatch reduction because it chops up the grass into tiny pieces which are then considered to be mulch. Lawn mowers with grass catchers tend to be somewhere in between.