Terran's Tips

Core Aeration and Seeding Your Lawn

What is Core Aeration?

Core Aeration is a process by which a machine (aerator) removes plugs, approximately 1” in diameter and 2-5” long, from the soil.

Why Aerate?

The answer is quite simple. It is without a doubt impossible to keep soil from at some point becoming compacted.       

For the most part, everything that comes in contact with your turf has the ability to aid in its compaction. Obviously equipment such as lawn mowers are going to have a much bigger impact than a garden wagon used occasionally for transporting mulch, etc., but everything matters. Dogs, especially ones that remain outdoors the majority of their life, are a very common cause of compaction as they have a tendency to continually retrace their steps through the yard and especially around its perimeter. If left neglected, trails of matted grass begin to form which soon turn to trails of dirt. Homeowners or their maintenance service who continues to travel the same paths when maintaining the turf produce heavy compaction which many times develop into ruts from the path of the tires of their lawn mowers. The possibilities for compaction are endless.

The simplest way to alleviate this problem is through core aeration. In this area of the country we have primarily clay soil. The problem with clay soil is it naturally has very little pore space for water and oxygen (know as macropores and micropores). As a result of this, less compaction is needed to suffocate the soil and what grows in it. Roots need oxygen, water, and space to grow and compaction impedes all of this. A common misconception is when you have problems with grass growing or runoff that you should de-thatch the yard. This is hardly ever the case as the turf would have to be badly taken care of for a long time to truly warrant de-thatching. Most of the time, and what is usually not realized, is that aeration will solve these problems as well as reduce thatch buildup, and not at the expense of your wallet or your yards appearance.

Benefits of Aeration 

  • Relieves compaction and increases the permeation of water and nutrients deeper into the soil.
  • Increase oxygen levels in the soil, aiding in root growth and decomposition of thatch and organisms.
  • Tines from aerator sever roots, rhizomes, and stolons of the turf. The turfs natural response is to produce more roots. A more extensive roots system results in denser more lush turf.
  • Aids in drainage by reducing the amount of run off and allow the water to infiltrate the soil, which further aids in increased drought tolerance.
  • Lawn will require less water.


Seeding and aeration go hand in hand, especially with cool season grasses. In our area of the country the cool season grass that is mostly used is a Tall Fescue Blend. This seed is bred to be drought resistant, heat resistant, and resistant to invasive grass and weeds. For areas that are shaded by large trees, many times the only option for grass is fescue. We suggest that for your large trees your have them thinned to allow some light to penetrate (not to mention the many benefits it has for your tree as well). In addition, for areas that already contain fescue, they should be aerated and overseeded at least once a year (early spring or late fall). For areas that have yet to be seeded now is a good time to take a look at trying to establish fescue.

Vertical Mulching

Very closely related to aeration is vertical mulching, which is basically aeration for your trees. Vertical mulching is a process where 2” diameter holes are drilled approximately 12” deep with a power auger. They are evenly spaced in an 18” x 18” grid spanning 8 feet out from the trunk of the tree to the drip line. They are then backfilled with mixtures of pea gravel, sand, and/or compost. This process, like aeration with turf, disrupts the soil, alleviating compaction and providing a well aerated column to allow the penetration of water and oxygen, the exchange of gas to take place, as well as tree root colonization. It is ideal that this area is then covered with mulch. (See Terran’s Tree Tips – March 2007 for more benefits of mulch around trees)

If you have areas in your yard that are tough to get grass to grow, whether it be Bermuda, zoysia, fescue, full shaded areas, or areas with full sun aeration is something to be strongly considered. While seeming to be a very simple project, aeration, overseeding and vertical mulching definitely have a lot more to it technically and should be best left to someone who knows a lot about.

If you are interest of any of the services mentioned please call our office and setup a free estimate. An ISA certified arborist will be sent out to better analyze your situation and recommend what is best.

Please email joanna@woodlandtree.com or call us at (901) 309-6779.

Posted by Mark Allen at 14:16