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Why Dethatch a Lawn?

Lawn Basics
4 min read

Why should you dethatch your lawn? Excessive thatch can become a breeding place for insects and lawn diseases and keep water from penetrating the soil. It can also prevent grass roots from pushing deep into the soil. The experts at Jonathan Green can explain why managing thatch is essential for a healthy lawn.

Jonathan Green is a leading supplier of cool season grass seed, soil enhancers, fertilizer, and organic lawn and garden products to professional customers, such as sod growers and independent retailers, including garden centers and hardware stores, throughout the United States.

What is Thatch?

Thatch is a layer of organic matter, consisting of living and dead stems, shoots, and grass roots, that builds up between the crown of the grass plants and the soil layer. It is typically the result of a soil imbalance or improper lawn care.

Thatch is a symptom of a lack of adequate microbial activity in the soil that is most often caused by acidic soils (pH 5.5 or lower), poor soil aeration and drainage, and improper watering methods.

A small amount of thatch can be healthy, say up to ¼ inch, and provide insulation against temperature extremes and fluctuations in soil moisture. Too much thatch, however, will increase the turf’s susceptibility to lawn diseases and fungus; reduce its tolerance to cold, drought, and heat stress; and rob the soil of its ability to absorb water, oxygen, and nutrients efficiently.

How to Manage Thatch

Remove a plug of lawn to determine whether your lawn has too much thatch. Measure the layer of thatch between the top growth and the root zone. If it exceeds 1/2″ in depth, you should use a heavy metal rake or thatching machine to remove the thatch and keep it to a minimum.

Adjust Acidic Soil

Take soil tests periodically to monitor pH levels in your lawn. You can do this with a pH tester that you will find in most garden centers and hardware stores. The lawn’s pH should be in a range between 6.2 and 7.0.

If the pH is low (below 6.2), be sure you have Mag-I-Cal® Plus for Lawns in Acidic & Hard Soil to adjust it. This is a natural, humate-rich, three-in-one “soil food” that rapidly raises soil pH, loosens hard soil, and stimulates soil microbes.

Aerate the Soil If the soil is very compacted, use Jonathan Green Love Your Soil®  to loosen and aerate it organically. Love Your Soil® will also feed soil microbes, make the soil more alive and porous, enhance root development, and provide about 25% more soil-loosening power than MAG-I-CAL® Plus to increase the breakdown of thatch.

Aeration can be done mechanically with a core aerator, a gas-powered machine that will remove small plugs of soil from the ground. To reduce costs, consider renting the core aerator machine from a local home improvement center or equipment rental center and share it with a neighbor or two.

Aeration should be done every year or two, depending on the severity of the thatch, the condition of the lawn, and how much foot traffic there is on the grass. If you continue to use Love Your Soil® annually, mechanical aeration of the lawn should not be necessary.

Water Properly

Homeowners with irrigation systems tend to overwater their lawns, thinking that more water will make the lawn greener. This is not usually the case.

Established lawns don’t typically need more than about one inch of water a week, which translates to 25 to 35 minutes per zone, watering once or twice every week. This will help the roots of the grass grow deep into the ground and make the lawn more drought-tolerant. Water in the early morning to avoid excessive evaporation. If the weather is hot and dry, increase the frequency of watering to three or four times per week at 25 to 35 minutes per zone.

For more tips on why you should dethatch a lawn, visit Jonathan Green online or visit your nearest independent retailer for reliable lawn and garden advice that will help you achieve great results.  

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