Liquid Dethatcher: Does It Work?

Written by Mike Futia

Updated January 12, 2023

Liquid dethatcher is a relatively new method in lawn care, and many people may feel confused if this is a product that actually works. 

Dethatching lawns is a time-and-labor-intensive process, usually requiring a power raking technique or electrical equipment. 

Therefore, it's tempting to believe that the process can be made easier simply by spraying the lawn!

So, does liquid dethatcher work?

It does appear liquid dethatcher is an effective method of reducing thatch. 

Studies have recently been published about the effectiveness of dethatcher products, and while it is still early days, the results appear promising. 

Liquid dethatcher is much less disruptive to your grass and soil than mechanical dethatching methods, breaking down thatch with microbial activity.

Read on to learn everything you need to know about liquid dethatcher.

What Is Liquid Dethatcher?

First, let's address what thatch actually is. 

The thatch level lies directly below the grass and on top of the soil layer. Thatch is made up of bits of dead grass and rhizomes, otherwise known as root shoots (horizontal sub-roots protruding from the grass). 

Some thatch is normal as it helps the soil to keep moisture, prevents it from overheating, and helps protect the roots when we walk over it. However, when that level of thatch starts to thicken, it can damage the grass. And so removing the thatch layer has many benefits.

A thick layer of thatch (anything greater than half an inch) makes it difficult for water and oxygen to reach the soil. The soil is then more susceptible to temperature fluctuations, excess water, or drought. 

You can check the level of thatch in your lawn by cutting a wedge from it down past the roots, like this:

lawn sample

Looking for thatch

Measure the light brown layer between the grass and the soil. Anything less than half an inch means that you should leave it be! Anything more than that is when dethatching needs to take place. To learn more, read about the pros and cons of dethatching your lawn.

Liquid dethatchers use bacteria that naturally break down thatch. If thatch has accumulated to the point that it's damaging to the grass, it's likely these bacteria aren't present at levels adequate to break down the thatch. 

Therefore, liquid dethatchers are used to add this bacteria back into the soil. 

Types of Liquid Dethatcher

Liquid Dethatcher #1: Thatch Digesters

This natural product adds bacteria and enzymes to the soil that work to break down thatch. 

The thatch is broken down into humus, which then acts as a natural fertilizer for the lawn. Some products may also contain ingredients that promote healthy grass in other ways. 

The issue with thatch digesters is that you’re buying a product with live organisms. It's impossible to know if the product you are getting still contains live bacteria!

Even if the product is within the date for effective use, it may have been in conditions (too hot, or cold) that killed the bacteria. 

Liquid Dethatcher #2: Thatch Removal Products

Instead of adding bacteria to the lawn, thatch removal products aid the bacteria that are already present in the soil in doing their job more effectively. 

These products feed the organisms so they reproduce and reach a level at which they can break down the thatch buildup to normal levels. 

DIY Liquid Dethatchers 

Some websites claim to have figured out the secret to making liquid dethatchers from ingredients found around the house. 

Ingredients include molasses (which is actually found in many liquid dethatcher products), beer, soda, mouthwash, ammonia, and dish soap). 

They claim the yeast and sugar in some of these ingredients feed the bacteria and increase the level of those good bacteria in the soil. The ammonia adds nitrogen, which is also needed for the bacteria to thrive. 

While that seems to make sense, it's questionable whether the quantities of sugars, yeast, and nitrogen in these ingredients would be effective. Other ingredients, like the soap and mouthwash, would seem to be counterproductive to bacteria growth. 

It's difficult to know if it actually works! As with many DIY natural solutions, these products are not tested by any laboratory. It's particularly difficult when dealing with something that doesn't provide immediate results. 

Liquid dethatchers can take years to work, so those claiming their lawns "look better" immediately are probably seeing results from other sources such as good weather conditions. 

Research And Science On Liquid Dethatchers 

Previous methods of dethatching by manual processes have been shown to be effective, such as using an electric dethatcher or a dethatching rake. (That said, we don't recommend trying to dethatch with a regular rake or a mower attachment).

However, as the liquid dethatcher method is still relativity new, there is not as much research to back this method up. However, the research that is just starting to come out looks promising.

A Korean study evaluated the effectiveness of dethatchers on golf course soil. It showed that using microorganisms (as found in thatch digester) in combination with fertilizer yielded better results than using a fertilizer alone!

Another study in 2022 looked at the effect of the enzymes (as used in liquid dethatcher) on turfgrass and found that it did help to manage thatch thickness. Recent research does appear to be in favor of liquid dethatchers at this stage. 

How Fast Do Liquid Dethatchers Work?

Using liquid dethatchers is more cost-effective and less labor intensive than manual methods. However, don't expect instant results. 

In fact, the process can take several years to work fully. 

The dethatcher needs to be applied over several seasons, and the added or aided bacteria need time to do their job. The thick layer of thatch will have built over a long time, and breaking it down is also not a quick procedure. 

Luckily, a thick thatch level will not immediately kill your grass— so you can afford to be patient with the process!

How Often Should You Use Liquid Dethatchers?

Liquid dethatcher works best in early spring when the grass is going to be growing at the fastest rate. 

If you live in a cold climate, you'll need to wait until the ground is fully thawed. Once you start the process, you should apply the dethatcher every few weeks throughout spring. 

You should not continue using dethatchers during the summer months, as the grass will already be under stress due to heat and dryness. Dethatching at this time may overtax the grass and damage it. 

Grass will be most resilient in the spring when conditions are ideal. A good idea is to check the thickness of the thatch before starting the second season of treatment. If the thatch layer is reduced, then you may already have an adequate level of bacteria in the soil. 

Remember: Too much bacteria can remove the thatch altogether, and a thin layer of thatch is perfectly healthy!

You shouldn't have to dethatch your lawn more than once pear year, max.

How To Speed Up Liquid Dethatchers

A well-aerated soil will do a better job of promoting the bacteria to work. By manually aerating your soil, you can speed the process up slightly. 

This can be achieved with an electric dethatcher, which may seem to defeat the purpose of using a liquid dethatcher. However, it's actually a good combination!

Another option to aerate the soil is a manual scarifier rake or a vertical mower. The last method is core cultivation, where cylinders of soil are dug out of the lawn and allowed to break down on the surface. 

This method even helps by physically removing some of the thatch from the soil while aerating it! This should also help, as the bacteria added to the soil will have less thatch to break down. 

With any of these aeration methods, it's best to do it twice per year; in early spring, and late summer. 

Does Liquid Dethatcher Work? Final Thoughts 

Recent research certainly appears very promising when it comes to liquid dethatchers being able to reduce the level of the thatch layer. 

However, we’ve yet to see anything about the long-term effects of this method, or the overall quality of the grass once the thatch is reduced. 

As we’ve discussed in this article, this method uses the natural properties of the soil rather than chemical agents. As such, it seems likely that the results will not be harmful!

Before trying to dethatch your lawn, it’s important to first make sure that the thatch layer is actually an issue. If that layer is half an inch or less, you may inadvertently inflict damage to your yard instead.

Always remember: Removal of thatch is just one method for improving your grass! Other procedures such as top dressing and aeration are also important for maintaining the overall health and appearance of your lawn.

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Mike Futia

My name is Mike, and I'm the owner and founder of My lawn care advice has been featured on Family Handyman, Home & Gardens, Gardening Etc., and Apartment Therapy. I love nothing more than helping my readers achieve their dream lawns. That's why I started, where I share all of my best tips and tricks for keeping a lawn healthy and well-maintained. You can read more about our mission on our About Page.

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