Thatch,which develops in lawns between the layer of green vegetation and
the soil surface, is a tightly intermingled layer of living and dead stems,
roots, rhizomes, plant crowns and other plant parts.The rate at which your lawn will develop thatch
depends on the type of turfgrass and your location.In addition to the species of grass, the
level at which you manage your lawn can impact the rate of thatch accumulation,
which occurs when the rate of thatch production is faster than the rate of decay.Rapid thatch accumulation can result from
excessively high mowing, heavy fertilization, vigorous turfgrass cultivars,
excessive soil acidity, poor drainage, reduced soil insect activity and reduced
levels of soil fungi and bacteria.
How Thatch Affects Your Lawn Quality Thatch accumulation greater than 1/2 inch in depth creates conditions that
could result in the deterioration of your lawn.A thick layer of thatch leads to a reduction in water and fertilizer
penetration into the soil, which results in less resistance to drought, reduced
rooting into the soil, increased sensitivity to temperature and moisture
extremes, and interference with the performance of pesticides.It also makes your lawn more susceptible to
insect and disease problems. As thatch
build-up increases, your lawn will be less responsive to fertilizer,
irrigation, and other lawn management practices. (back to top)
Preventing Thatch Accumulation Excessive fertilization can increase thatch accumulation by producing
vegetation faster than the rate of decomposition.Frequent application of high concentrations
of nitrogen can create this condition. Mowing
grass regularly at proper heights (generally 2.0 to 2.5 inches) can also help
slow thatch build-up.The clippings only
need to be removed when grass is wet or extra long and a layer of clippings
remains on the surface.Grass clippings
returned to the lawn do not significantly contribute to thatch layers. Clippings are primarily composed of water, and
the remaining dry matter is easily integrated into the soil by insects and bacteria.
In contrast, lignin, which is found in the
roots, stems, rhizomes and crown tissue of grasses, is not easily digested and
is the most significant contributor to thatch accumulation.
In many lawns, thatch accumulation is the result of slow decomposition. Soils that are very acidic or very alkaline tend
to have slower rates of thatch decay.Maintaining
a soil pH between 6.0 and 7.0 encourages microbial degradation and earthworm
activity.Poorly drained soils are also
susceptible to thatch because of a reduction in insect and bacteria activity.Earthworm activity is also important in
reducing thatch because it is one of their food sources.
Topdressing, the process in which a thin layer of soil is added onto the
turf, is another preventive approach to thatch.This light coating of soil helps improve the environment at the soil
surface and facilitates microbial activity.The soil used for topdressing should be similar in texture to the
original soil in order to prevent drainage problems due to
incompatibility.Peat moss or other high
organic materials should not be used, as these products will add to thatch
deposition.Topdressing should not be added
on a lawn with an existing thatch layer as it will create a serious layering
problem. (back to top)
Thatch Management After thatch accumulation has begun, but before the layer exceeds 0.50 inch in
thickness, there are several methods for getting rid of thatch.Dethatchers (such as power rakes, lawn
combers, and vertical mowers), mower blade attachments and core aeration are
commonly used practices. A more convenient approach is using a liquid dethatcher such as Dethatcher Blend, which contains natural enzymes and bacteria to safely remove thatch without mechanical devices that may damage your lawn. Dethatching should
be done during a cool season when several weeks of good growth and recovery can
be expected. Fewer weed problems occur in
early fall, and two growing seasons (fall and spring) follow before the lawn
encounters summer stress. Very early
spring is the next best time for dethatching.
The best approach to thatch control is aeration. Core aeration is the process in which hollow
tines are used to remove plugs of thatch and soil from the lawn and deposit
them on the surface. Rainfall or
irrigation then incorporates the soil into the thatch layer.The addition of soil to the thatch layer results
in increased microbial activity and breakdown of thatch.Core aeration can be supplemented (or replaced)
with chemical liquid aeration to help break down the thatch layer.GreenerGreenGrass Aerator Blend is a natural product for liquid lawn aeration with beneficial bacteria and enzymes. (back to top)
Thatch,