Lawn Care/Maintenance/Equipment/Maintenance Equipment/Power Rake
Thatch is a mix of dead and living material that accumulates on the soil surface. Thatch accumulates due to over-fertilization, over-watering, and/or soil compaction. A small amount of thatch is desirable because it helps to moderate soil temperature fluctuations and provides a cushion on the soil surface. But too much thatch interferes with water and air movement, reduces fertilizer and pesticide response, and increases disease and insect activity. Eventually, roots may start growing in the thatch, and since thatch does not hold much water, the turf then becomes very susceptible to drought stress.
Dethatching machines are power rakes with blades that cut through the thatch, loosening dead and live organic material and bringing it to the surface of the lawn. Dethatching machines that cut with knives or blades are much better than machines with flexible rake-type tines and removable attachments for a rotary mower blade. The organic material removed by the dethatcher should be raked, removed, and used as a mulch or placed in a compost pile.
If the thatch layer is 0.5 inch thick or more, use a number of passes in different directions.
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The dethatcher produces large quantities of refuse, and the lawn will look very ragged for a time. Reseeding may be necessary after dethatching lawns with 0.5 inches or more of thatch. Thatch thicker than 1.0 inch may have to be removed with a sod cutter and the lawn reestablished.
Kentucky bluegrass and fine fescue should be dethatched in the spring (April)
or in the fall (Sept.) when it is still actively growing - never in the summer.
Zoysiagrass, on the other hand, should be dethatched in the summer. Tall fescue
and perennial ryegrass rarely develop a thatch problem. Close-up of
Thatch Mat
Source: Texas A&M Turfgrass Program