During a lawn dethatching service, a piece of equipment called a dethatcher is run through the grass to tear the thatch layer out of the lawn. The idea is to mechanically extract thatch in order to allow more water, oxygen, and nutrients a chance to reach deep into the soil.
Unfortunately, this equipment can also cause collateral damage when the dethatcher pulls up not only the thatch but a significant amount of healthy grass as well, exposing the lawn to the risk of weed seed germination in the bare areas.
A lawn aeration service, on the other hand, works in a different manner. The equipment called a core aerator used in this process removes small cores of soil about a half inch wide by two-three inches long throughout the lawn. Aeration helps loosen the soil, which permits more oxygen to penetrate into the root zone, dealing with anaerobic bacteria.
These improved conditions also allow the abundance of beneficial naturally-occurring microorganisms in the soil to help decompose the excessive thatch layer at a faster rate. Both services accomplish the same goal but a lawn aeration service does so without the possibility of damaging your lawn in the way a lawn dethatching would.
That's why dethatching has fallen out of favor as a recommended lawn care practice.
Beyond its effect on the thatch layer, aeration also provides other advantages to your lawn. It improves soil structure and allows for stronger, thicker root growth - the necessary foundation for a healthy lawn and the best weed control.
In addition, when an overseeding is performed at the time of the aeration, the process can generate better seed-to-soil contact, which is crucial for seed germination and gives those seedlings the best possible chance to survive and thrive.