How to De-Thatch a Lawn

Managing the thatch level in your lawn is a vital part of maintaining a healthy lawn. Part of lawn management is knowing when and how to de-thatch your lawn.

A little thatch, 1/2 inch or so, is actually healthy for your lawn. It will protect the grass from drought and heat. The problem occurs when the thatch becomes thicker, blocking water and nutrients from reaching the soil below. Signs of a thatch problem include weeds in a lawn with good weed control, failing grass growth, and poor drainage. You can always check by digging out a small chunk of lawn and seeing just how thick a layer of debris there is above the soil. This layer of debris, old grass stems and leaves, bits of bark and leaves from your trees, is thatch. Thatch buildup is most often a problem in over watered, over fertilized lawns or lawns where long clippings are left on the grass.

Option 1

If your thatch is a bit thick, but not too bad, try aerating your lawn. Pulling plugs of soil will draw up microorganisms to the thatch layer which break down the material into nutrients for your grass.

Option 2

Rakes your lawn. Dig the tines of the rake into the grass to pull up the thatch layer, but try not to damage the grass itself. Remove the raked material immediately.

Option 3

Rent a power de-thatcher or hire a lawn company with one. This is a device that looks much like a power lawn mower, but the blades go vertically to cut through the thatch instead of laterally to cut the grass off. If you rent a power de-thatcher, ensure the owner explains its settings and operation to you carefully. You will have to set the height of the blades to suit your lawn as well as the spacing of the blades. The blades should not dig into the soil. Different types of grass need different spacing. Tougher grasses should have the blades closer together, more delicate grasses need wider spacing. It is preferable not to pass over the same section more than once as it increases the chance of damaging the grass.

Rake up the thatch that is brought to the surface by a power de-thatcher immediately. If this material is left on the lawn the problem will just begin again.

After De-thatching

Your lawn will look less than perfect after de-thatching. Expect it.

Water the lawn gently and minimize traffic for a month or so to let the grass reestablish itself.

Fertilize your lawn lightly after de-thatching to encourage reestablishment.

Tips To Prevent Thatch Buildup

Get a mulching mower. This mower chops up the grass blades into very small pieces and redeposits them on the lawn. It provides excellent fertilizer for the grass and the small pieces decompose easily, preventing buildup.

Make a yearly raking part of your lawn care plan. This breaks up the thatch a bit each year and pulls up the excess, saving you from having to rent a mechanical de-thatcher every few years.