|Use collected thatch as mulch|
Those brown spots on your lawn are likely thatch, a tangled combination of dead grass, roots and leaves. Thatch on your lawn can block air, sunlight and water from reaching the ground. Thatch may also block grass seed and fertilizer from reaching the soil surface.
Dethatch rake or thatch rake
Call it what you want, the purpose of the unique dethatch rake is to pull the thatch from the ground leaving the healthy grass behind. The dethatch rake has a two-sided head that is about 15 inches wide. Tines on one side are for pulling up thatch; tines on the opposite side are for cultivating.
So why not use a garden rake instead of a dethatch rake?
Dethatch rakes now come with a pivoting head that is adjustable by loosening two wing nuts. This added control will allow you to adjust the angle of the tines for a deeper or shallower swath through the grass. You might want to adjust for a shallower swath if you have a very thick layer of thatch so the rake is less likely to hop or catch in the tangled mess. You will need to make repeated strokes, but each pull of the rake through the grass will be easier to make.
How to dethatch the lawn
Start by mowing the lawn to two inches or less. With shorter grass height, you can more readily see the thatch and the grass is less likely to wrap around the dethatch rake’s tines where it could be pulled from the ground.
Place the dethatch side of the rake on the ground, holding the handle just like you would if using a garden rake. The tines on the dethatch side of the rake are straight while the tines on the cultivating side of the rake are slightly wavy.
Use collected thatch as mulch. Spread 3 to 4 inches under evergreens, pile around roses to protect them for the winter, or use the thatch as a mulch topper on outdoor planters.