Aeration Explained

Aeration is the best cultural practice for all plants. We will start with turf. The main reasons for aerating turf is to decompact soil, maintain a thatch layer, and incorporate organics creating topsoil. Soil gets compacted for many reasons including seasonal (snow), equipment (lawn mowers), and traffic (any areas walked on, where children play, or where you enjoy the beautiful lawn you deserve).

Compaction of soil is detrimental to plant growth. It inhibits root growth, does not allow water penetration to root zone, and does not allow for oxygen transfer by the roots (yes, roots need to breathe!!).

It is best to understand the reason for thatch, why and how turf grasses produce it, and how to maintain it properly.

Thatch is a part of the grass plant that is often mistaken for grass clippings that haven’t degraded. Different types of grass produce thatch at different rates and thatch production can be triggered by environmental factors, but more often by nutrients available to the plant. One of the most common types of grass, Kentucky Bluegrass, is prone to rapid thatch production when there is an abundance of available nitrogen (one of the main ingredients in plant food and fertilizers). 

An overabundance of the thatch layer is often the cause of disease. Retaining too much moisture creates an environment that fungi thrive in. The roots of grasses can migrate into the thatch layer causing stress on the plant as temperature varies drastically (as much as 20 degrees F in a 24 hour period, where topsoil varies by about 2 degrees F). Insects also thrive in this environment, which can cause blooms, where the environment is conductive to the pests for enough time, without any mitigating conditions, such as predators, to keep the population at bay. These situations often require additional costs to intervene, which proper maintenance and knowledge could have avoided or reduced.  

A popular belief is that thatch is a bad thing and simply needs to be completely removed on a regular basis. This simply isn’t true and it does serve a purpose. It moderates soil temperature and retains moisture in the root zone of grasses. Instead, the thatch layer should be maintained regularly, and if excessive thatch cannot be maintained through the aeration process, a closer look may be necessary. More frequent aeration or amending the fertilizer program may be the best solutions. Dethatching is a process of removing nearly all of the thatch layer, and is used to get the layer to a point where it can be maintained through aeration. The stress dethatching can put on turf, especially if done incorrectly can be detrimental.  

 

Where do leaves and grass clippings go when they are spread over our lawns with the mowers? The answer is they typically don’t compost like we would like to believe. In fact, it often causes an acidic condition, where grasses prefer alkaline soils. Proper composting requires mechanical intervention. This is most evident in large piles of organic material, like leaves. Years after the piles were created, most of the material is still leaves that have only minimal effects of composting. Turning over the pile and incorporating inorganic material expedites the composting process. The same goes for lawns, and regular aeration is how this is accomplished. The composition of top soil is not widely known, but it is basically clay or sand and organic material. Is your soil mostly clay or sand? If so there are options, you can add topsoil (the composition of which was just mentioned), or you can incorporate organics to the clay and sand. Leaving this material on the surface does not achieve this, it needs to be incorporated into the soil.

These are often overlooked when the topic of aeration comes about. The truth is it is just as important for them as it is for turf.

When installing plants, soil is often tilled or amended to create the optimum growing medium. After being planted, not much attention is given to these plants, besides the aesthetics, like pruning. Aeration benefits these plants as well by breaking up the soil and allowing for oxygen transfer in the roots. This decompaction reduces the chances of binding roots and girdling (a condition in which the plant chokes itself, so to speak). There are several ways of accomplishing aeration to landscape plants, but care must be taken to avoid root damage. The preferred way that I am a proponent of, is by using water under pressure injected using a probe. Water is pumped in breaking up soil and displacing it, a proportion of this space ends up being replaced with air. Our services, add the amendments (such as fertilizers, pH correctors, and others) to the water. These bind to the soil and offer the optimum growing conditions.

The majority of feeding roots on trees are not as deep as what most would think. The image of a tree with a large taproot, reaching down to water far below the surface, is often what comes to mind. The truth is the majority of feeding roots in trees are near the surface (6 to 12 inches deep) and due to alteration of the soil environment, many suburban and urban trees lack deep taproots entirely. Evidence of this is noticed when compaction, often resulting from equipment traffic in the rooted area, causes dieback and not uncommonly complete demise of trees. Trees are extremely dependent on oxygen transfer via the roots. Decline and death of trees when areas get swampy or flooded are often a result of the lack of oxygen transfer. Aeration and root zone fertilization are the best maintenance practices to keep trees healthy.   

  

As you can see, aeration is important but often neglected maintenance. Much attention gets pushed towards fertilizer, supplements, and watering, all of which are important, but will lack results if the growing medium and root areas are neglected. If you have questions or concerns, please contact us. We are your local solution.