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Should I aerate or dethatch my lawn first?

by Jackson White

In order to keep your lawn looking attractive and a rich green color, it is important to pay attention to its maintenance. Unfortunately, many people do not know the intensive task of maintaining grass lawns – including the processes of dethatching and aeration.

The unfortunate fact is that taking care of grass is not as easy as you might initially assume; it actually needs a lot of effort on your part for it to remain strong and healthy. In fact, any professional landscaper will advise you to develop an annual maintenance plan, and include procedures like aeration, dethatching, liming, overseeding, and fertilization.

In this article, we will focus on aeration and dethatching, as they have different purposes, and you will apply them at different times. Both have the common purpose of helping the roots of the grass penetrate the soil better, and they promote easier nutrient, water and air flows. That leads to the question of which one you should do.

As a general rule, it always helps to check the activity of microbes in the soil. If your soil is healthy and supports sufficient microbial activity, then you will only need to dethatch once every season, and aerate one or two times a year (depending on the soil type). That ideally makes dethatching the first process before aeration.

What is the difference between dethatching and aeration?

It is easy to confuse the two processes because they sound very similar when you first hear of them. After all, they both seek to remove any excess plant and organic matter from the soil, in order to allow the plants to get their nutritive needs freely and allow the grass and roots to breathe.

However, they are actually 2 different methods that seek to help your soil in a variety of ways, so it is important to know how they differ.

In the case of dethatching, you need to understand what thatch is – and it refers to any natural organic matter that is on the surface of the soil. This includes grass clippings, fruit and flowers from nearby trees, leaves, and so on. Thatch is useful when it is in moderate amounts, because it acts as a nutrient source, as well as regulating the soil temperature and moisture. However, it becomes harmful when the layer is too thick, because it forms a barrier between the air and soil, and suffocates the roots and kills the plants present. The aim of dethatching therefore is to remove the unnecessary thatch layers, and ensure that the layer present is conducive to soil health.

On the other hand, aeration is useful to loosen up the soil, and works when dethatching cannot help. Soil tends to go through many changes over time and compresses due to gravity, weight, and pressure. The result is that the soil feels harder as time goes by, which results in compression of the roots and killing of the grass. The aim of aeration is to allow the soil to breathe by removing small plugs from the surface of the soil in order to release pressure.

When should you dethatch?

It is quite easy to know when you should dethatch, because you only need to press the soil to see if it feels spongy. If the ground is too soft and gives under your hand pressure, that is a sign of too much thatch. Examine the new shoots as well; if they cannot emerge from the soil that is also a sign of too much thatch.

If the problem is severe and you see that your plants are stunted in growth, then you need to get a professional service to dethatch the ground. If you are doing it yourself, you need to leave a thin layer of thatch to ensure the ground is healthy enough to not lose moisture too fast.

The time of dethatching will depend on the type of grass, the soil conditions, and the weather condition – so the most preferable time is during the spring months. Note that you do not need to dethatch the whole lawn, as it will depend on your lawn’s needs.

When should aeration be done?

The process of aeration is to create small-size holes in the ground while removing the thatch plugs. It is usually done using a lawn aerator, which has small sharp tines that go deep enough to remove the plugs while aerating the soil.

The frequency of aeration depends on your soil type. For sandy soil, for instance, the aeration can be done once a year, but clay soil needs aeration 2 or 3 times a year.

Differences between dethatching and aeration

The dethatching machine removes the upper layer of dead organic material in order to allow air circulation to go through the soil.
The aerator machine creates small holes in the soil and removes plugs to promote better aeration.
The process makes the top soil loose enough to allow overseeding.
You will not need to do overseeding before aeration.
Works best when you have a lot of dead organic matter on the top layer of the soil that makes the ground spongy
Works best when the thatch is very thick.



Whether you decide to aerate or dethatch first will depend on the thickness of the thatch. If it is less than 0.5 inches thick, then aerate first, while dethatching is best if the thatch is over 0.5 inches thick.

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