Dethatching - Additional Information

Lawn thatch is commonly mistaken for lawn debris. All said and done, lawn debris will eventually turn into thatch but when you’re looking to address the problem, the two are not interchangeable.

Lawn thatch exists in the layer between the crown of the turf and the soil. It consists of the shed and decomposing grass roots, grass stems, organic material, stolons and rhizomes mixed together with living roots and grass tissue, insects, and microbes. 

The debris consists of effectively anything above the crown within the canopy of the turf. This could include clippings, leaves, branches, and other materials. 

Thatch is composed of 25% Lignin with the remainder primarily consisting of cellulose and hemicellulose. Lignin is slow to break down by microbial degradation with only a few species able to consume it. Cellulose and Hemicellulose are much quicker to decompose. 

For the most part, thatch is a positive thing. It’s home to beneficial insects and microorganisms, Earthworms, holds moisture, provides cooling to soil roots and provides cushioning on sports playing surfaces. It also helps to filter and limit pesticides from leaching through soil into groundwater. 

It becomes an issue when thatch builds up faster than it can be broken down. The primary cause of this is over application of high-nitrogen fertilizers. This has two effects – it causes excessive growth (and therefore too much thatch) while also degrading the bio-diversity and populations of soil microorganisms that are required to break it down. 

This issue can also be compounded by soil compaction problems and excessive pesticide use that harm the soil biome. 

When thatch reaches levels exceeding 0.5 inches, it causes a multitude of problems. Turf roots start growing into the spongy (often moist) thatch layer and struggle to grow deeper. This becomes a larger issue during high heat when the thatch dries out, becoming hydrophobic (Repels water) which in turn dries out the roots and restricts airflow, promoting anaerobic conditions. 

Because water and oxygen cannot penetrate the hydrophobic crust of the thatch, you end up with standing water, that in high heat and humidity promotes pathogenic microbes that increase the likelihood of diseases as well as provide a breeding ground for plant-feeding insects such as Chinch Bug. 

Thatch really should be able to be maintained without extra intervention through proper cultural and maintenance methods. 

My lawn care program incorporates a combination of Molasses (bacterial food source) and specific types of Bacteria and Fungi that are effective at breaking down thatch (Lignin and Cellulose) and can quickly turn it into natural, usable nutrients the turf can use.  

Find information on that program Here

Dethatching is only recommended when thatch levels exceed 0.5 inches within the soil profile. 

Bear in mind, this is an aggressive process and will cause some damage to the turf. It should only be done when the temperatures are lower, earlier in the season or in Fall when the turf is actively growing and able to quickly repair itself. It should never be done during times of high heat and drought. 

If you’re looking for ways to organically control thatch without the need for dethatching – follow this link to check out the Lawn Care Program. This incorporates Molasses (bacterial food source) and specific types of bacteria and Fungi that feed on thatch (Lignin and Cellulose) and can quickly break it down into natural, usable nutrients the turf can use.  

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