Thatch is a tightly intermingled layer of living and dead stems, leaves and roots which accumulates between the layer of actively-growing grass and the soil underneath.



Excessive thatch creates a barrier that prevents the movement of water, air and fertilizers into the soil; thus, Power-rake is sometimes necessary for some lawn suffering from thick layer of thatch (more than 1/2 inch).

However, Power-raking should NOT be done on regular basis for the following reasons.

• Power-raking removes beneficial thatch (less than 1/2 inch) from your lawn. In fact, a thin layer of thatch is desirable because it increases wear tolerance of lawn.
• Power-raking is highly injurious to the turf.
• Power-raking "mossy lawn" may worsen the problem because it will spread the spores of moss to the entire lawn. (none of moss-killing  products kills the spores!)

Instead of using power-rake service annually or bi-annually, it's always better to prevent building excessive thatch by

• Topdressing the lawn once a year with compost
• Using less amount synthetic fertilizer
• Proper irrigation
• Core-Aeration

 Another common mistake is power-raking immediately after core-aerating. This practice will break the plugs and backfill the holes with the same soil. Consequently, the benefits of core-aeration is greatly reduced.