Grass thatch is a tightly intermingled organic layer of dead and living shoots.

Grass thatch is a tightly intermingled organic layer of dead and living shoots.  Stems and roots that accumulate just above the soil surface of your yard.  Itís not necessarily grass clippings even though they may contribute to the problem.  Thatch accumulation is due to either over-fertilization, over-watering, and/or soil compaction of the lawn.  My information on thatch control was provided by turf grass specialist Dr. Brian Unruh with IFAS of the University of Florida.

Accumulations of thatch make very difficult.  While providing a home for turf pests, thatch reduces the effectiveness of insecticides and fungicides, by restricting their movement into the soil.  Water and air movement also are restricted, causing dry sots and uneven law growth.  Saturated thatch dries slowly, stimulating disease problems.

Thatch is a plant residue problem.  A healthy lawn produces vegetation very rapidly.  As long as production of plant tissue exceeds the rate of decay, thatch will accumulate.  Overwatering and over fertilizing contributes to thatch buildup by stimulating excessive growth.   Leaving excess clippings on the lawn after mowing will add to a thatch problem.  Failure to maintain a favorable soil environment for bacterial growth decreases the rate of thatch decomposition.

Thatch control require proper lawn management and when necessary, physical thatch removal.  Only the minimum amount of fertilizer for good growth should be applied. As will encouragement of excessive growth should be avoided.  Liming of acid soils may help increase thatch decomposition by stimulating bacterial action.

Proper watering and mowing are important.  Maximum decomposition occurs if the soil is moist, but is retarded if itís too wet or too dry.  Lawns should always be mowed at the recommended frequently.  If not more than one-fourth to one-third of the leaf tips are removed at each mowing, thatch seldom increases.

If thatch becomes a problem, corrective actions should be taken as soon as a buildup is noticed.  One method is topdressing applying, a layer of new soil over the lawn.  Frequent, light applications are better than one heavy application.  The texture and quality of topdressing material should be as close as possible to that of the soil on which your grass is growing.

The other basic method of correcting a thatch buildup is verticutting also known as vertical mowing.  As the name suggests, vertical mowing is a process of cutting grass vertically with a series of evenly spaced metal blades mounted on a steel shaft which revolves at high speeds, the space between the vertical blades and their depth of penetration into the thatch can be varied to remove as much of the thatch as is desired.  However, improper spacing, or cutting too deep, can seriously damage or even kill your lawn.  Itís a job for experts.  So, if vertical mowing becomes necessary we recommended that you contact an expert lawn service for assistance.

For more information on turf thatch contact the Gulf County Extension Service @ 639-3200 or visit our website:  or www.  for Fact Sheet ENH152.