While the power rake and the dethatcher are essentially used to perform similar tasks, there is considerable difference between the two. A power rake generally uses rotary blades that help slice down the thatch in the soil, while the dethatcher uses a thin spring tine that helps pull up any loose debris on the grass. The power rake is much more powerful and aggressive as compared to the dethatcher. The dethatcher is mainly used to pull up thatch from the soil, usually from the surface. Since the dethatcher is gentle, you can easily use it one or two times in a year for a safe and healthy lawn.