Should you Aerate?

Throughout the growing season, lawn enthusiasts (and lawn worriers too!) tend to focus their thoughts to mowing, fertilizing and controlling weeds.  Often, aeration comes up in conversations between neighbors as a point of concern as well as what is it and do we want it or not?

First, a little background.  Anything that is put on a lawn or done to a lawn should have a rationale.  In the case of aeration, the reason(s) for having the lawn aerated are many.  The main benefit is opening up the upper soil profile to increase air movement (hence the term “aerate”), replicating what would be the case if the lawn were in its original state of a pasture, open grassland or forest floor.  In those situations, air would move in and out of the soil readily and nurture the roots the plants growing in it as well as the small organisms that are vital to healthy plants.  A secondary benefit is the improved movement of fertilizer and pest control agents into the soil.

Unlike undisturbed soils, most lawns are growing on and in very disturbed soils.  The construction process of homebuilding literally destroys the soil profile, drainage potential and nutrient availability of the substrate that turf plants need to grow in.  The good news is that after 40-50 years of tree debris droppage and turf root and crown turnover, soils can once again provide for the air, water and nutritional needs of the lawn grasses.  One big step in the meantime is to aerate and accelerate the process.  In short, the answer to the question posed in the title of this post is: YES.

So, how does one aerate a lawn?  It’s pretty simple; you can rent an aeration machine from a hardware store or rental store, haul it home in a pickup truck, fire it up and run it over the lawn two times.  It’s best to make the first pass in a north-south direction and the 2nd one in an east-west direction to achieve good coverage.  Or, the other option is to hire a lawn service that offers lawn aeration.

Some tips on aeration:

-Inspect the tines; if they are dull, ask the owner of the machine to sharpen or replace them.

-Insist on a machine that removes cores of soil/turf, not just pokes holes in the ground.

– Use the buddy system, since the average machine weighs about 200 pounds.

-Wait 2-3 days after aeration for the cores to dry out and then mow the lawn to shatter them into small pieces to serve as a topdressing and filter into the thatch and open holes.   

The most common question we get with aeration is how often and when should it be done.  Ok, that’s 2 questions.  The answers? 

-On average, once a year in the spring or fall.  Newer lawns should be aerated more frequently than older lawns. 

-Lawns should be aerated when they have a few weeks to recover from the injury of the aeration process.  For Kentucky bluegrass and turf type tall fescue lawns, early to mid-spring and early fall are good times.  For zoysia lawns, early summer is the preferred timing.

Follow up procedures to aeration include overseeding and topdressing.  Since the turf surface is opened up, grass seed is more likely to germinate than if it were just tossed on a non-aerated surface; about a 30% germination rate is to be expected, which will thicken up the lawn.  Topdressing is not practical for large lawns, but for smaller spaces, applying a light layer of finished compost with a corn shovel and then dragging it in with a stiff tine rake will create channels of loosened soil for roots to grow into and boost the health of the turf plants.

John Fech
Horticulture Extension Educator at Nebraska Extension
John Fech is a horticulturist with the University of Nebraska-Lincoln and certified arborist with the International Society of Arboriculture. The author of 2 books and over 200 popular and trade journal articles, he focuses his time on teaching effective landscape maintenance techniques, water conservation, diagnosing turf and ornamental problems and encouraging effective bilingual communication in the green industry. He works extensively with the media to extend the message of landscape sustainability, making over 100 television and radio appearances each year.
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2 Comments Add yours

  1. Chris Amberg says:

    Hi John – we have a tow-behind manual John Deer aerator that we put weight on and use at least once per year. The article mentions the rental of a very heavy gas fueled aerator. What advantages would I gain by doing this versus my current method? My aerator has hollow blades and removes cores. Thanks!

    1. grobigred says:

      Hi Chris,
      Your set-up would also work well, the goal is to pull out 3 inch cores, so however you do that is fine.

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