If your lawn has issues with brown spots or water puddles where water just cannot penetrate the soil, you may have heard of the method of just poking holes into the lawn, or lawn aeration. Is it legit or is it just a myth?
Lawn aeration is necessary for lawn maintenance once a year. It opens up the thick top layer of thatch and compacted clay soil to allow for a better flow of water, oxygen, and nutrients to penetrate into the soil. It is beneficial for plant growth with better root growth and more soil organisms in promoting soil fertility.
In this article, we will look at what lawn aeration is, and go through some studies to see if it is really necessary for your lawn.
1. What is lawn aeration?
Aeration is also called perforation, staking, or core drilling (or drilling holes in the ground).
Using a machine, lawn aeration can be done by removing or extracting small plugs or cores of soil (with a diameter of 1/2 or ¾ inch) out of the lawn and depositing them on top of the lawn.
Aeration holes created by lawn aerators are typically 1-6 inches deep, 2-6 inches apart. The extracted cores of soil will decompose back to the lawn in 2-4 weeks.
Lawn aeration can also be done manually using a hand aerator, which is shaped like a fork with spikes. Hand aerators or walking on spiked shoes are, however, not very effective and can even contribute to further compaction of the ground. This is because hand aerators punch into the ground, push into the soil, and do not remove the soil.
2. Benefits of lawn aeration
The major benefit of lawn aeration is that it opens up compacted soil and clears the thatch which is dead grass accumulated on the top layer. This layer of dead grass prevents water, and oxygen from getting into the soil. Perforating holes into the thatch would allow more oxygen, water, and nutrients to enter the soil.
Aeration also frees toxic gases from the earth, created by the death and decay of microorganisms, and prevents them from building up to dangerous levels.
Because of more moisture, oxygen, and less toxic gases in the soil, more soil organisms such as earthworms, microbes, and plants can also flourish. The plants will also show healthier growth, with longer roots.
Soil microbes are important for soil fertility as they can decompose organic matter in the lawn into nutrients readily available for plant uptake, thus promoting stronger plants and better growth.
These benefits are proven by many studies comparing lawns aerated and not aerated.
One study shows that the number of soil microbes increases after aeration (Franz, Taylor & Riina, 2005).
Another study shows that aeration has significantly increased the density of grass growing in an area, the length of grass roots, and root depth (Sharbazery & Gareeb).
|Without aeration||With aeration|
|Plant density||456 plants/m2||520 pants/m2|
|Active root length||12.5 cm||14.5 cm|
|Root depth||25 cm||37.5 cm|
Another study also found a correlation between aeration and increase in plant root length (Sayed et al., 2012). It found that the best results come with a higher perforation density of 216 holes/m2 (21.6 holes/square feet), than 144 holes/m2 (14.4 holes/square feet).
3. How do you know if you need to aerate the lawn?
There are five situations when your lawn is probably too compacted and needs aeration:
-When there are brown spots on the lawn. Those are the thatch, or dead grass accumulating on the top like a mat preventing water from penetrating into the soil.
-Water pools on the surface in puddles rather than penetrating into the ground, after watering or the rain. If this happens, the soil is water-repellent, in other words, hydrophobic.
-When the soil becomes compacted due to heavy use from human activities, animals, being driven upon by cars and machinery.
– When it is in heavy clay soil.
-if the soil was dry without receiving any watering or rainfall for a while, it would most likely be water-repellent or hydrophobic.
– Finally, you can take a soil sample of 6 inches deep. If the grass roots only reach down to the first 2 inches, your soil is probably too compacted.
4. What happens if you don’t aerate your lawn?
If you do not aerate your lawn and it is exposed to soil compacting events, thatch (dead grass) or turf grass will build on the top layer of the grass like a mat.
Thatch is a thick top layer of dead grass that builds up over time, which soaks up all the water and prevents water, fertilizer, and oxygen from penetrating into the soil.
The soil underneath would then become more and more compact, resulting in fewer soil microbes and organisms for healthy soil, and poor plant growth with shorter roots.
5. When should you not aerate your lawn?
The best time to aerate lawns is when the grass just comes out of dormancy and begins a period of vigorous growth. This is because aeration will do some damage to the grass which can recover quickly in its active growing period. Another reason is that competition from weeds is also minimal during this time.
For warm-season grass such as Bermuda grass and zoysia grass, the best time to aerate is during their active growing season in mid-summer in June and July.
For cool-season grass such as tall fescue and Kentucky bluegrass, the best time would be end of summer to early fall (around September).
6. How often should you aerate the lawn?
For home lawns, it is enough to aerate lawns only once a year, even under heavy use.
7. Should you mow the lawn before aerating?
You do not need to mow the lawn before aerating. But you should water your lawn two days prior to aerating it to make it moist, but not wet so that the machine can penetrate deeper into the soil.
Avoid aerating areas with stones and heavy clay soils. Also, mark sprinkler heads and underground cable and utility lines before aerating so they will not be damaged.
It is definitely necessary to aerate lawns that are compacted as it can help loosen the soil for a better flow of water, oxygen, and nutrients near the root zone. It helps increase the density of plants, root length, root depth, and for better microbial activity. It is best done by a machine than using a hand aerator once a year, at the beginning of the active growing season.
Apart from lawn aeration, you can also use a wetting agent to improve water absorption for your lawn.
Aveni, M. (2013). Aerating Your Lawn. Virginia Cooperative Extension. Virginia Tech. Publication 430-002
Franz, E., Taylor, R. & Riina, C. (2005). Soil Aeration Background. “The Little Things that Run the World” Soil Ecology Program, Roland Park Country School.
Sayed, C., Ahmed, D., Raoudha, G. & Khaula, A. (2012). Effects of the density of the mechanical aeration on the resistance to penetration of a turf soil and its impact on the plant root behavior. Agricultural Segment: 3(1) AGS/1578, 2012
Sharbazery, A. O. M. & Gareeb, B.A. (2018). Effect of Aeration and Compaction on Some Characters of a Turf Grass Mixture Under Sulamani City Conditions. Journal of ZankoySulaimani, Special Issue, 2nd Int. Conference of Agricultural Sciences. pp.37-42