Thatch Control in Lawns and Sports Turf: Causes, Problems, and Proven Solutions

Thatch is one of the most common, and misunderstood, problems in lawns, golf greens, and sports turf. Left unmanaged, it can restrict growth, reduce surface quality, and create long-term turf health issues.

In this article, based on an episode of the Grass Me Up podcast, we explain what thatch is, why it builds up, and the pros and cons of the main thatch control methods, from scarification to biological degradation.

What Is Thatch?

Thatch is a layer of dead organic material that accumulates just below the grass surface. It consists of:

• Dead grass leaves and stems
• Moss
• Weeds that haven’t been controlled
• Roots and stolons that decompose slowly

Over time, this material builds up and forms a dense layer that impedes water infiltration, nutrient uptake, root growth, and soil biology.

In turf management, this layer is often referred to as the O-horizon, and unlike in natural ecosystems, a large O-horizon is not desirable in lawns or sports turf.

Why Thatch Builds Up

Thatch accumulation is rarely caused by a single factor. It’s usually the result of high growth combined with poor decomposition.

1. Excessive Growth and Stress

• High fertiliser use accelerates leaf production
• Drought stress causes leaves to die faster
• Dead material accumulates faster than it can break down

Dry conditions are especially problematic because organic matter only decomposes when moisture, warmth, and oxygen are present.

2. Overuse of Iron

Iron should be used sparingly and only for specific aesthetic or functional reasons (e.g. events or tournaments).

Excessive iron use:

• Suppresses soil microbial activity
• Inhibits saprotrophic microbes responsible for breaking down thatch
• Leads to long-term organic matter accumulation

3. Copper-Based Products (A Major Issue)

Copper-based turf products are one of the most damaging contributors to thatch buildup.

Key problems with copper:

• Highly toxic to soil biology
• Persistent (does not break down in soil)
• Accumulates over time
• Reduces microbial decomposition of thatch

Copper products are often sold as “fertilisers” but used as fungicides, and their long-term impact on soil health can be severe — something already well documented in vineyards and increasingly seen in turf systems.

Avoiding copper products is one of the most effective ways to reduce thatch long term.

How Thatch Affects Turf Performance

Excess thatch can:

• Restrict root penetration
• Reduce water and nutrient movement
• Increase disease pressure
• Create soft, unstable playing surfaces
• Impede recovery from stress

Managing thatch is not optional — it’s essential for healthy turf.

Thatch Control Methods: Pros and Cons

1. Scarification and Raking

Pros

• Immediate physical removal of thatch
• Effective when done correctly

Cons

• Can damage fine turf or golf greens
• Labour-intensive
• Disruptive during the growing season

Scarification isn’t always suitable, especially on delicate or high-performance turf.

2. Microbial Products

Microbial thatch control products were among the first biological solutions introduced.

Challenges

• Often not suited to low pH, iron-treated turf
• Microbes may die before application
• Quality and consistency vary widely
• Competing with existing soil microbes

There are already trillions of microbes in healthy soil — the issue is activation, not introduction.

3. Enzyme-Based Products

Enzymes target specific components of thatch, particularly lignin, which is the slowest material to break down.

Pros

• Can assist in organic matter breakdown
• Used successfully in some hydroponic systems

Cons

• Mixed results in turf
• Many enzymes are not designed for soil use
• Often adapted from industrial or detergent applications

A Modern Approach: Stimulating Existing Soil Biology

Rather than adding microbes or relying solely on enzymes, a more effective strategy is to stimulate the microbes already present in the soil. This is the basis of Eutrema’s unique Thatch Degrader.

This approach:

• Works with local soil conditions
• Activates saprotrophic fungi and bacteria
• Enhances natural lignin breakdown
• Improves thatch decomposition over time

When soil microbes are fed correctly, thatch becomes softer, more pliable, and easier to degrade or remove.

Real-World Results from Thatch Degrader

In controlled trials, treated turf has shown:

• Visible reduction in thatch density within weeks
• Activation of fungi responsible for organic matter breakdown
• Improved soil biological activity
• Faster degradation even under tarped conditions

Similar technology is used in agriculture to break down maize stubble — proving the concept works at scale.

When Is the Best Time to Treat Thatch?

The ideal conditions for biological thatch breakdown are:

• Moist soil
• Moderate temperatures
• Active microbial populations

After prolonged dry weather, wet periods provide an excellent opportunity to stimulate decomposition and reduce thatch naturally.

Final Thoughts

Thatch buildup is not just a maintenance issue — it’s a soil biology issue.

To manage it effectively:

• Avoid excessive iron and copper products
• Don’t rely solely on mechanical removal
• Focus on stimulating natural decomposition
• Work with soil biology, not against it

With the right approach, thatch can be controlled sustainably without damaging turf quality or soil health. Why not check Eutrema’s Thatch Degrader and stimulate the existing biology of your soil!

Article by Dr Russell Sharp

If you would like to keep up to date with subjects just like this, you can listen to our other podcasts! Links can be found bellow:

Hydroponics Daily Podcast: https://podcasts.apple.com/us/podcast/hydroponics-daily/id1788172771

Cereal Killers Podcast: https://podcasts.apple.com/us/podcast/cereal-killers/id1695783663

Grass Me Up: https://podcasts.apple.com/gb/podcast/grass-me-up/id1818978949