Thatch is the dead grass that builds up on the soil's surface over time. A small amount of thatch is actually healthy for Bermuda grass. But if thatch buildup reaches more than ½ inch tall, it can cause significant problems. It interferes with the soil's ability to absorb air, water and fertilizer and restricts its root growth, making Bermuda grass more susceptible to drought and cold damage. The best time to dethatch Bermuda grass is in midsummer when the grass is growing most rapidly.
Cut a wedge out of the soil and turf from several areas of the lawn. If the thatch in those wedges is thicker than 1/2 inch, it is time to dethatch.
Water the lawn the night before you plan to dethatch it.
Rake the lawn with your power rake. Use even, chipping strokes to bring the thatch to the surface. Go in one direction first, then go over the lawn again at a 90-degree angle to the first direction.
Rake up the thatch immediately with a flexible tine rake. You may have to make a few passes or even pick some up by hand, but gather up and bag as much of the thatch as you can.
Water the grass. Use a light spray so that you don't wash away any newly-exposed soil. Water the lawn more frequently than usual for the next few weeks.