Dethatching and Power Raking. What is a Thatch layer?

The thatch in a lawn is the layer of organic debris that forms at the base of the grass plant, where stem meets root/soil. Over time material that does not break down quickly will build, and the thatch layer grows. As well, more mulching rather than mowing/bagging will leave significant accumulation of dead grass over time, that should be removed. Although no officially "thatch", this debris layer of dead grass should be cleaned and will be via dethatching.

A thatch layer of 1/2" is beneficial as it serves to  guard against temperature fluctuations as well as conserve moisture in the soil When the layer gets too thick it becomes detrimental. It harbors beneficial microbes that enhance lawn health. Over 1/2" and problems begin too arise. Fertilizer and water cannot properly penetrate and the grass roots begin to get trapped in the thatch. Lawns with thick thatch are much more vulnerable to the stresses of heat as air flow is greatly reduced. Dandelion growth is promoted when heavy thatch lawyers are present. 

Dethatching is less aggressive than power raking and s intended to remove excess thatch layer as well as excess grass cuttings. Dedicated dethatching machines will use spring thines which limit the depths to which they can penetrate. Power rakes have rotating flails that can either be set higher to only dethatch, or set low to aggressively power rake. Dethatching  in our area should be done in the spring/early summer. It should not be done when grass is either dormant or stressed. A lawn should be dethatched roughly every 3 - 5 years.

Power Raking serves the same purpose as dethatching; it removes the thatch layer. However it addresses more substantial thatch layers and should be followed with aeration, fertilizer and lime treatment if ph levels are out. As power raking dig much farther into the lown, into the soil layer, the lawn will require re-seeding and a top dressing of a turf blend. As this is a fairly involved process we recommend dethathcing as a first step if the thatch layer is not extreme.  

Dethatching or Power Raking are quoted per job. Quite a few factors come into play pricing a dethatching as the thickness of the thatch and size of the yard effect the amount of work required. Prices typically start at $120.