What is Lawn Aeration and is it Necessary?

    Perhaps you have heard the term ‘Aeration’ thrown around while doing research on lawn maintenance but have been confused or curious about what exactly it means to aerate and is it even necessary to incorporate into your lawn care routine.

    The simple answer is Aeration removes plugs or “cores” of grass and soil to make it easier for lawns to take in all the essential nutrients necessary for it to flourish into the beautiful green color we all desire our grass to have.

    The basic idea behind lawn aeration is that, like all living things, your lawn needs to breath. In addition to the physical grass plant needing to breath, the soil under it also needs to breathe. But how do you accomplish this? And when should you aerate your grass?

    Strictly speaking, most lawns do not need to be aerated to grow grass. Almost all lawns will benefit from aeration, and a great lawn demands it every 3-5 years depending on use. However, lawns experiencing heavy foot traffic, excessive thatch (>1 inch thick) or grown on heavy, clay soils will benefit most (1).

    An Overview – Key things to know about Lawn Aeration

    • Invigorates roots and stimulates new growth.
    • Reduces soil compaction.
    • Reduces thatch accumulation.
    • Enhances movement of water and nutrients into the soil.
    • Smooths out bumpy lawns.

    Why Aerate?

    If you have noticed that your turfgrass is not looking its best or that water pools on the surface and has difficulty penetrating through the soil surface, it may be time to aerate your lawn. Clay soils and lawns that bear heavy foot and vehicle traffic are especially notorious for needing aeration as they become compacted over time (2).

    Another contributing factor is Thatch, an organic layer made up of woody tissue from dead grass roots and stems. It is found under the grass plants right at the soil line. Normally, it breaks down just like leaves in a compost pile, but poor draining conditions inhibit the microorganism responsible for reducing the thatch layer. A layer of thatch greater than 0.5 inches reduces water infiltration. Grass growing in these conditions takes root in the thatch instead of the soil where roots are less protected from summer heat. A thick layer of thatch may feel spongy, or you may notice that water runs off the lawn without penetrating the soil (3).

    After a long, hot and dry summer, your lawn needs some time to breathe. A fall aeration removes finger-sized plugs from your lawn – loosening compact soil and allowing nutrients, water and oxygen to penetrate the root system

    Besides the fact that aeration will improve your soil’s nutrient and water intake capabilities, aeration offers these additional benefits:

    • Reduces puddles from forming on your lawn
    • Reduces stress from heat and drought
    • Enhances seed germination
    • Strengthens roots
    • Makes lawns less susceptible to disease

    When and How to Aerate your Lawn

    Determine if it is time to aerate your lawn by using a shovel to dig a square-foot section of grass about six inches deep and examine. If the grass roots do not extend further than two inches deep into the soil, your lawn would benefit from aeration (2).

    During the summer, your lawn is also stressed, which leads to thinning areas on your lawn. Overseeding in the early fall helps to reestablish your lawn before winter dormancy – ensuring you’ll have a full, lush lawn come the spring.

    Note: To avoid damage, do not aerate a lawn that has been seeded or sodded within one year of planting.

    Prepare your Lawn for Aeration

    Water the lawn thoroughly one to two days prior to when you plan to aerate your lawn. Apply at least 1″ of water to the grass; this can be measured by placing a shallow bowl or glass jar in the middle of the watering zone. When 1″ of water has fill the container you know the grass has been sufficiently watered. Watering the lawn will help the aerator machine penetrate the soil and pull out soil cores much more easily than if the soil were dry (2). Be sure to first flag irrigation heads and other hidden objects in the lawn so that you will avoid them when operating the aerator over this area. If you do not have an irrigation system, use a garden hose and sprinkler to water the lawn (1).

    Note: Depending on your climate, the best time of the year to aerate cool-season grass, such as fescue, bluegrass or rye, is in August through October when the grass is breaking its dormancy and begins the period of active growth; the best time to aerate warm-season grass, such as Bermuda, Zoysia or St. Augustine, is April through June. Core aeration and overseeding are sometimes done together, and the latter is more effective in the North in fall than in spring (4).  

    Photo: Source

    Time to Aerate!

    A mechanical core aerator is the best equipment to use for aeration. The tines on this type of machine are hollow on the inside so that they pull soil cores out of the earth. Other aerators, such as those with spikes don’t work as well and some turf experts suggest they may actually further compact soils. You can rent core aerators from most garden centers for about $30 to $75 for a few hours. Be sure to use help from others when lifting the equipment, as the spiky cores make the machine very heavy and awkward. Likewise, read the operator’s manual carefully prior to use.

    Note:  Run the core aerator over the lawn in a pattern that covers the area only once or twice depending on the level of compaction.

    Final Applications

    If you are now wondering what to do with these strange looking soil cores spread all across your lawn the good news is that they can be left on the ground after aeration and allowed to decompose. If you use organic products on your lawn, you can rake the cores into piles and throw them in your compost bin to be made into future nutrient dense compost for your lawn. If you wish to take a hands off approach, removal of the cores is not necessary at all. It should take about two to four weeks for the soil cores to break down naturally depending on the weather and soil composition. Either option you choose, be sure to sprinkle organic compost over the lawn to fill in the holes. Now is a perfect time to overseed grass and organic fertilizer to lawns as this is an ideal time to do so.

    Photo: Source

    Alternative Methods of Aeration

    Aeration Sandals

    If renting a lawn aerator for $200 per day or hiring a landscape crew is not in your plans, maybe a pair of lawn aerator sandals will do the trick – simply strap them on to your regular shoes. Use them while you’re mowing the lawn, you’ll get an extra workout and your lawn will be able to breathe again. If you decide to use Lawn Aerator Sandals, here are a few points to remember:

    • They work best if the lawn is slightly damp or moist (not soaked through)
    • Leaves and other debris will clog the spikes & reduce their effectiveness
    • If your balance isn’t great, it may be advisable to use a cane while aerating
    • Some manufacturers don’t recommend using with a lawnmower
    • The sandals will arrive completely disassembled. You will need to manually attach the straps and the 10+ 2” spikes to each sandal.
    • Look for models with a sturdy sole
    • Several straps to securely attach them to your shoes
    • Solid metal spikes that protrude through the sole of the sandal to penetrate the lawn below
    • They are not removing a core of sod and soil, only pushing a hole into the ground (4)


    1. https://www.canr.msu.edu/news/improving_soil_conditions_for_turf_with_fall_aeration
    2. https://web.extension.illinois.edu/askextension/thisQuestion.cfm?ThreadID=21429&catID=154&AskSiteID=34
    3. https://www.extension.iastate.edu/news/yard-and-garden-properly-aerating-lawns
    4. https://www.ag.ndsu.edu/yardandgardenreport/documents/should-you-aerate-your-lawn

    Top Photo: Flickr // James Clarke