Aerating and Dethatching

Lawn Aerating

Lawn aerating is probably one of the most important, yet most neglected tasks that is really necessary for a good looking healthy lawn. Over time the soil and layer of thatch next to the soil compact. The more compact the soil is the harder it is for water and nutrients to penetrate it. Aerating is essential to help loosen the soil so that water and nutrients can soak in and not just run off.

Lawn Aerator Types

There are two key types of aerators that can be used. The Spike aerators and the core or plug aerators. I won’t spend too much time on the “Shoe” aerators I have seen sold. Please don’t waste your time or money on that! The Spike aerator either has a spike or a triangular shaped wedge that pokes a hole in the ground. These do no help much if you have compacted soil, as a matter of fact they probably aggravate the problem as the act of inserting the spike further compresses the soil around it!

Core Plug Lawn Aerator
Lawn Aerator - Plug Style

Core or plug aerators actually remove a “plug of soil. There are the best aerators. They remove plugs of soil giving the compressed soil around the hole space to expand into. There is the added benefit that the aerator will cut through any built up thatch. This breaks it up and aids it along in the decomposition process. One objection to plug aerators is the plugs of soil that they leave behind. They are somewhat unsightly. If they are objectionable then the recommendation is to rake them in after aerating. That will help break them up and sift it way back into the lawn bed. These types of aerators are typically more expensive then the spike type, but are well worth the extra cost.

When to Aerate

The best time to aerate is in the spring for the warm season grasses and in the fall for the cool season grasses. It is best to do your fertilizing and the additions of any other supplements at the same time.

When aerating you want to first travel in one direction, lets say north to south. Run the aerator in parallel paths next to each other so that you cover the entire lawn in adjacent runs with the aerator. Next repeat the process but in an East to West direction so that you are in essence creating a cross-hatch pattern. Again, make sure to cover the entire lawn in parallel paths that are adjacent to each other.



Certain lawn types respond well to detatching. typically grasses that grow in clumps such as Bluegrass and Fescues can be easily dethatched with no negative side effects. Warm weather grasses like Centipede and Bermuda eventually develop an interlaced network of rhizomes. These rhizomes make up the bed of the lawn. Running the tines of a pull behind de-thatcher pulls that network apart and typically leaves the lawn looking pretty horrific.
When to dethatch
Dethatching should be done when the layer of thatch reaches 1/2 inch in thickness. One good way to see how much thatch has built up is to pick up one of the plugs after core aerating and measure the amount of thatch that is on the plug. The plug left behind by the core aerator is a good snapshot of what you turf looks like and an excellent way to measure how much thatch you have.
Lawn Dethatcher

If you are going to dethatch your warm weather lawn, consider hiring a competent yard care company. They should use a power de-thatcher that will cut through the rhizomes rather then pull through them. Alternatively, you can rent one and do it yourself.  Make sure that when you dethatch you do so in the spring for summer grasses and in the fall for Cold weather grasses. Those grass types will respond better during their respective seasons.

One last note on dethatching, if you aerate regularly the tines of the aerator will cut through the thatch, opening it up and giving it a chance to decompose. This gives nature a chance to solve the problem of thatch for you and increases the amount of time between de-tatching.