Lawn thatch is composed of a tightly intermingled layer of stems, leaves and grass roots, which accumulates between the vegetation and the soil. Too much thatch increases the turf's susceptibility to lawn diseases, reduces its tolerance to drought, cold, and heat stress; and hinders the movement of air, water, fertilizers, and nutrients into the soil. In severe cases roots of the grass will not grow into the soil but only take root in the thatch layer making the turf susceptible to drought and heat stress.
If a lawn is building thatch faster than the microbes can break it down, this indicates that the lawn is lacking beneficial microbes. The cure to a thatch problem is not physical removal of the thatch, but by managing thatch in a lawn by stopping the improper cultural practices that are killing microbes in the soil. The cure to preventing and curing a thatch problem isn't mechanical removal of the dead grass, instead it is to stimulate beneficial microbial activity in the soil.
99.99%+ of lawns DO NOT need to have the thatch removed via power raking or vertical cutting. Please contact your local lawn care expert before scheduling or performing a power rake service.
Thatch that is 1/2 inch or less is considered normal. More than 3/4 inch of thatch can be a major problem for the lawn.
Thatch will accumulate in a lawn if the production of dead material (organic matter) exceeds the ability of the microorganisms in the soil to break down the organic matter. Thatch build-up occurs in lawns that have "dead soils" and thatch is a symptom of the absence of beneficial microbial activity. Thatch buildup happens if there is poor soil aeration and drainage. Improper lawn watering practices (usually too much water or too frequent water), cold soil temperatures, the use of chemical pesticides, and the use of synthetic fertilizers are all factors that increase thatch accumulation in lawns.
When a lawn's thatch layer is greater than 3/4 of an inch thick it may need to be mechanically removed via power raking or vertical cutting.
Lawn aeration is an excellent way to stimulate beneficial microbial activity in soils. Air is vital to soil health and aeration should be perfromed at lease once per season.
Start by stimulating beneficial microbial activity by implementing proper lawn watering practices, lawn mowing practices, core aeration and lawn fertilization.
Power Rake, but only if it is before the lawn has greened-up in the spring. This lawn care service is rarely necessary
Double Aeration to bring air into the soil.
Sprinkler Audit to fix any improper lawn watering practices. Make sure to follow the principals of the 1-2-3-2-1 lawn watering technique.
Stop all fast release nitrogen, synthetic fertilizer, herbicide or fungicide applications.
Apply Synergy with Corn Gluten Meal and Humate Soil Conditioner to stimulate beneficial microbial activity.
Thatch does not accumulate in a lawn from mulching grass clippings. Thatch accumulates from the lack of microorganism activity and buildup of organic matter due to the absence of a living soil.
Lawn Mowing - Never cut more than 1/3 of the blade of grass at one time. Mulching the grass clippings does not increase the tendency to build thatch. Change the mowing height to 2.5 inches in the spring and fall and increase the height to 3 inches or taller in the summer.
Lawn Fertilizing - Fast release nitrogen lawn care applications will result in a decrease in thatch decomposition and an increase in thatch production rates. Always avoid high dosages of synthetic nitrogen sources like ammonium nitrate because they are salt based and kill beneficial microbes. Organic fertilizers stimulate beneficial microbial activity in the soil.
Lawn Irrigation - Avoid light and frequent watering. Always irrigate the turf deeply and infrequently. This entices the roots of the grass to grow deep into the soil instead of the thatch layer. The lawn may look worse for a few weeks, but deep and infrequent watering will stimulate the roots to establish into the soil instead of the thatch.
Lawn Pesticide - Pesticides negatively affect desirable microorganism and earthworm populations. Lawn care pesticides should be avoided unless absolutely necessary.
Thatch only accumulates in a lawn when organic matter accumulates in a lawn, because there is an absence of beneficial microbial activity to break down and decompose the organic matter. Thatch buildup is caused by improper lawn watering, improper lawn mowing, and or the use of chemical fertilizers. The best way for managing thatch in a lawn is to create an environment that stimulates beneficial microbial activity, which is called building a living soil. The microbes in the soil will be able to break down the organic matter and keep the thatch layer at a normal level - 1/2 inch of thatch or less in a lawn is considered healthy.