Aerating A Lawn With A Lawn Core Aerator? Follow This

Aerating A Lawn
Aerating a lawn can cause more problems than benefits

Just like lawn dethatching and lawn rolling, I can see why you might think aerating a lawn with a lawn core aerator is necessary or even beneficial on an annual basis.

Not only is it often recommended gardening advice, but most lawn care companies do this as part of their regular service, organic gardening companies included.

The thing is, it can be beneficial if done right, but it generally isn’t done right, so I’m going to give a few lawn aeration tips here.

Aerating a lawn involves cutting round holes in the soil with a lawn plug aerator and pulling the core out. It can be a good thing, but only if followed by another important practice.

As an important aside, there is another method called spiking that makes holes in your nice organic soil without pulling any soil out. You may have seen those shoes with spikes on the bottom you can wear while walking on the lawn. This method is useless because although it is creating pore spaces in the soil, it is compacting the surrounding soil. Soil must be pulled out to get any benefits. So onto the lawn aeration tips.

Aerating A Lawn – What Is The Purpose?

The reason lawn aeration with a lawn core aerator is generally done is because it is thought to increase air and water penetration into the soil. While these are important organic gardening goals and it works for a very short time if enough cores are pulled from the soil, the effects are short-lived.

Here are the 3 biggest downsides:

  1. When the holes fill back in with the dead grass and soil that was pulled out, it can cause water issues. But more commonly the holes are backfilled with sand, which may cause major water problems, with patches of dry grass and patches of overly wet grass. This happens when sand is mixed into your soil that is a different texture.
  2. The grass is physically hurt by the lawn core aerator and if done regularly, the grass health can be greatly affected. Of course, the microorganisms are effected, too, especially fungi, which are integral in organic gardening practices for the health of the lawn. Regular aeration can severely decrease their population.
  3. If you are aerating a lawn during late spring or summer when the grass is directing most of its energy towards top growth, it will be forced to switch back to root growth to repair the roots that have been cut. This is very bad for the plants.

When Is A Lawn Core Aerator Necessary?

Aeration should not be necessary on an organic lawn that is healthy, but while you are in the process of transitioning your lawn to be healthy and perhaps moving to organic gardening methods, it can be very useful to create a healthier, less compacted soil environment and a denser, healthier root system.

All this will happen only if the tines are sharp, if the machine actually pulls cores out of the lawn, if it is done at the right time of year, and if it is followed by another practice.

The right time of year is generally fall, although early spring is okay, too. The other practice is discussed next and it is lawn top dressing.

22 Comments

  1. GreenerGreenGrass on November 17, 2010 at 3:07 pm

    You are so right about core aeration. Have you ever thought about using a liquid aerator? It works on a microscopic level by using opposing charges to push soil colloids apart, creating space in the soil for air, water, and nutrients. It’s great for both lawns and gardens.

    • Phil on November 17, 2010 at 6:58 pm

      It seems to me to be a band-aid solution rather than focusing on balancing the soil nutrients and increasing organic matter content and microbial diversity and numbers. Core aeration is also a band-aid solution when done alone, but when done as a means to reach these other ends, it is useful. Interesting idea, but I would rather add these things to my soil than ammonium laureth sulfate.

  2. Jason on January 22, 2011 at 4:05 am

    As a business owner I find that most of the calls we receive are from homeowners whose lawns are in decline. Aeration has been a great tool to help us renovate lawns.

  3. Gary on June 25, 2012 at 9:49 pm

    I have been doing aerating for over 4 years now. However i have a problem that I think has been caused by the aerating. I have hundreds of “mounds or hills” that look like giant ant hills which have made the entire lawn very bumpy. I noticed last Fall that hundreds of mounds, that looked like big ant hills were rising on the lawn.Each mound looked hardened like as if crystalized water….Now the lawn is so bumpy its hard to walk on and even harder to mow because its so un even. I found one way to rid these mounds is to manually walk the lawn and break up each mound by hand or raking back and forth…Has anyone else had this problem…??Garyjjflash7@hotmail.com

    • Phil on June 26, 2012 at 12:11 pm

      It seems there is something about your lawn that the ants find attractive, so fixing that issue will gradually decrease the ants. It could be that the lawn is too dry, lacking humus, imbalanced in nutrients, lacking a healthy soil food web, etc. It takes some knowledge to figure that all out, but it can be done. I’m not sure if your aeration will be contributing to it…

  4. Candace Ramlall on March 20, 2013 at 4:12 am

    Hi I have a question, if I wanted to aerate a sunflower plant for a project how would I go about doing this?? And would the deeper the aerated holes be more beneficial for the plant? Thanks

    • Phil on March 25, 2013 at 1:19 pm

      Hmm, I’m not sure exactly what you’re asking here.

  5. Steve on March 26, 2013 at 12:42 am

    I can’t believe nobody mentioned Overseeding. aerating without doing the other half of the equation is pointless

    • Steve on March 26, 2013 at 12:43 am

      Especially with bunch type grasses that don’t spread laterally

      • Phil on March 28, 2013 at 3:07 pm

        Definitely, if your lawn is sparse, you should overseed, but only if you also address why your lawn is sparse in the first place. Hopefully people aren’t using only bunch type grasses in the lawn.And the point of aerating is not really to prepare the lawn for overseeding. It’s to get beneficial materials down into the soil, like organic matter, minerals, and microbes. Certainly if overseeding is necessary, it should be done at this time, too.

  6. Dan on August 18, 2013 at 7:37 pm

    How does regular aeration hurt the microbial population? I thought it would be good for microbes. From what I’ve read before, as the cores lay on the ground and decompose, it encourages microbial life and it also helps decrease thatch due to the increase in microbes.I’ve been core aerating my uncle’s lawn 2 times per year since I bought my own tow plugger last year (so I’ve actually only been doing it for 2 years). Reason is: 1. He has extremely heavy red clay soil (red shale actually) which is very compact. 2. His lawn is Zoysia grass which thatches up really quick.So I figured it would be good for his soil. Also, I only mulch his grass, including all the leaves in the fall. And it’s looking pretty good so far. It doesn’t seem like I’m hurting it (so far).

    • Phil on August 22, 2013 at 5:21 pm

      Ya, 2 times per year during active root growth can be okay, especially if you add beneficial things into the holes such as fertilizers and inoculants. It may encourage some microbial life, while harming other microbial life. But the aeration itself is largely just a band-aid solution really – it doesn’t decrease compaction for very long. Compaction is a chemical and biological issue, not so much a physical issue.

      • Dan on September 16, 2013 at 9:02 pm

        Thanks for the advice. Great site by the way, just signed up my e-mail.What kind of inoculants would you recommend? I’ve heard raw milk, molasses, and other weird things like that are good for microbial life.

        • Phil on September 21, 2013 at 12:05 pm

          Milk can bring some benefits, but is also antimicrobial (it’s used as a natural pesticide). Molasses can be very beneficial. But those aren’t actually inoculants. My favorite inoculants are mycorrhizal fungi and ‘effective microorganisms’.

          • Dan on September 21, 2013 at 11:22 pm

            Oh I see, I wasn’t quite sure what inoculants were. I’m going to have to read your website more. Thanks for the tips.



  7. Ted on September 27, 2013 at 8:55 pm

    When aerating a yard, what is the desired, optimum speed of the core aerator?

    • Phil on September 29, 2013 at 2:15 pm

      I’ve never seen any research on that. I’m not sure how much it matters as long as the machine is performing well.

    • Dan on October 12, 2013 at 4:26 pm

      When I’m aerating, I usually try to run the tractor as fast as possible because it seems to eject the cores better. Just experiment as you’re doing it. The objective is to get good 3″ cores, the speed at which you do it doesn’t matter so long as the cores are coming out good.

  8. Gerald Penney on July 31, 2016 at 6:03 am

    I had turf laid onto a gravelly piece of ground and while the grass seems to grow well, there are patches of brown and it’s very fine. I cut it “long” to avoid damage. If the ground underneath the grass is too compacted, would aeration help?

    • Phil on July 31, 2016 at 3:02 pm

      Core aeration on its own doesn’t help much with compaction in the long run, but if you can backfill the holes with good compost, perhaps mycorrhizal fungi and perhaps appropriate fertilizers like calcium carbonate or rock dust, that could be very helpful.

  9. Philip Sherwin on June 2, 2017 at 4:24 pm

    I am creating a lawn after building a retaining wall, backfilling with fill dirt and topping with topsoil. First I seeded it with ryegrass, but now I’m ready to overseer with tall fesque. Should I core aerate before overseeding? It’s June here in North Eastern OK. What do you think?

    • Phil on June 5, 2017 at 3:14 pm

      I wouldn’t, especially this time of year. The only reason I would is if there was something I really wanted to get down into the root zone, like a mycorrhizal inoculant or a fertilizer of some kind, but that would be more appropriate in the fall or earlier in the spring.

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