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How to Manage Pests

The UC Guide to Healthy Lawns

Dethatching methods

Using a thatching rake

A thatching rake, available at lawn and garden stores, can be used on small lawns. A thatching rake has thick blades that are designed to dig into the turf and loosen the thatch layer.

  • Pull the rake across the lawn, bringing the thatch up to the soil surface.
  • Remove and discard the debris.

Using a vertical mower

For large lawns, use a vertical mower to cut through the soil surface. Known as a verticutter or dethatcher, this mower has a series of revolving blades that cut through the thatch and bring it to the surface. The depth to where the vertical blades penetrate is adjustable and should be determined by thatch thickness and your turf species. These mowers can be rented at rental equipment centers. It may be more convenient to have a professional do the job for you.

  • In general, grasses with a creeping growth habit tend to produce heavier thatch layers than bunch-type grasses so set the blades so that they cut about 1 inch into the soil and 1 inch apart.
  • For bunch grasses, set the blade higher and further apart.
  • Before dethatching, mow your turf a little lower than you normally would and lightly moisten the soil surface.
  • Run the verticutter across the lawn in one direction.
  • Once you have dethatched the entire lawn, make a second pass over the lawn at an angle perpendicular to the first pass.
  • Remove the debris with a rake and dispose of it.
  • Follow up by aerating, fertilizing, and watering as needed.
  • Overseed as necessary.

Photo of a thatching rake

Photo of a dethatcher

Photo of the blades of a dethatcher

Statewide IPM Program, Agriculture and Natural Resources, University of California
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