What Are Power Dethatchers and How Does a Lawn Dethatcher Work?

Posted on 5th May 2010 in Power Rakes

Power Lawn Dethatchers

Power dethatchers are also known as power rakes and thatching machines.  They are machines designed to remove thatch from a lawn. They are similar to a gas-powered lawn mower, but are bulkier and heavier (twice as much or more than lawn mowers). Typically two people are required to get one into or out of a truck or trailer. Along the bottom are rows of blades that can be set at different heights and widths apart depending on the grass type and amount of thatch. The blades can be set to go into the dirt and rip out the thatch or they can be set to slice through the thatch, which is then raked up later. Sometimes the second process is referred to as power raking, but many people use the two terms interchangeably.

Thatch

Thatch is the spongy layer of organic material that accumulates on the top of the soil line but below the grass. Most people don’t notice thatch in their lawn unless it gets especially thick or starts creating problems. As grass clippings, leaves and other lawn debris build up on the soil surface, the resulting thatch affects how water, nutrients, oxygen and light are able to reach the grass roots. Some thatch is good for the grass, insulating it and improving the grass’s ability to survive drought and high temperatures. Too much thatch can keep water and nutrients from getting to the roots, causing the grass to yellow, brown and die. If it is too thick, some of it should be removed to maintain good lawn health.

Determining Thatch Thickness

To figure out how thick the thatch layer is, use a coring soil probe that pulls up cores of soil. Then look for the spongy layer on top of the soil’s surface. If the lawn is large, take several cores from different areas to get an estimate of the average thickness and find any areas that might be problematic.

Deciding How to Remove Thatch

Once the thatch layer is around an inch thick, some sort of minor dethatching should be started. Using a manual dethatcher rake will keep the thatch from getting too thick. A power rake set on a higher setting so the blades cut the thatch rather than rip it out is great for less than three inches of thatch. At three inches or more, it is a good idea to dethatch with deeper blades to rip as much of the thatch out as possible. While it is hard on the grass and the lawn won’t look nice for a little while, it will be much easier to keep the thatch from getting too excessive and causing more problems than its removal did.

Dethatching

Dethatching can be done by professionals or a power dethatcher can be rented for around $50-$75 hours for four hours. At the rental center, have them help position the blades correctly or follow the manual directions. After dethatching a small section, check to make sure the blades are going in the correct depth. Roll the dethatcher along the lawn in rows or diagonals and then go crosswise against those rows to remove the most thatch. The thatch and grass pulled out will need to be collected and disposed of. An average-sized lawn with a thick layer of thatch can yield more than one pickup truck worth, or more if the thatch problem was extensive.

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