To thatch or not to thatch
Lawn thatch is an often misunderstood and miscontrolled problem.
Thatch, the buildup of dead grass between living grass and the soil, causes trouble for your lawn when it exceeds 1/2 inch thick. Excessive thatch prevents air, water, and nutrients from reaching plant roots. Cutting through and removing thatch combined with core aeration can improve your lawn’s health greater than supplementing with chemicals.
What it is and what it ain’t
Despite popular belief, short clippings dropped on the lawn after mowing are not the cause of thatch buildup. Clippings are very high in water content and breakdown rapidly when returned to lawns after mowing, assuming lawns are mowed on a regular basis (not removing more than one-third of the leaf blade). Thatch is caused by several factors, including grass type, excessive watering, soil compaction, high or low soil pH, or overuse of fertilizer and pesticides. Avoid overfertilizing and overwatering your lawn as this is better for the environment and promotes a healthier and more resilient lawn. It is important to determine the cause of the thatch otherwise it is likely to return each time you remove it.
Now what?
Remove a core of soil from the lawn with a trowel or shovel and measure the depth of the thatch, which is the layer of dead grass above the soil line. A layer that’s 1/2 to 1 inch thick can be removed with a stiff lawn rake. Deeper layers may require a power rake. For shallow thatch on small areas, use a stiff lawn rake. For small lawns with more than an inch of thatch, use a special thatch rake. Large areas and thick layers call for power rakes or vertical mowers, which are available from rental agencies and power equipment dealers. You may want to contact a landscape or lawn specialist to handle the job if it appears to be too much for you to handle.
When using a thatching rake, pull the blade-like tines across the lawn, cutting through the thatch. Work in small sections, and then remove the debris with a lawn rake. If the thatch requires the use of a powered machine such as a powerr rake or vertical mower, then adjust the cutters to slice just through the thatch layer. Check cutter depth after the first first few feet and reconfigure if necessary. Run the machine in parallel rows over the lawn and then again at 90° to the first pass. Remove debris with a lawn rake.
When your finished
The lawn will require some watering and fertilization to recover from the thatching. It may require overseeding which can be done while thatching your lawn. Make thatching your lawn part of your maintenance regimen to increase drought resistance and lessen the damages caused by insects and disease.
