Liquid lawn aeration is starting to be promoted more both by manufacturers of liquid aeration products and some lawn maintenance companies, but does it work? How does liquid lawn aeration compare to traditional core aeration?
I am also starting to see more DIY liquid aeration mixtures being promoted on the internet. How do these compare to commercial products?
What is Lawn Aeration?
It sounds as if it is a way of getting air into your lawn and indirectly that is correct. Lawns are popular because they make a great walking surface. The problem is that this foot traffic compacts the soil under the lawn. Compaction squeezes the soil particles closer together, forcing air out of the soil. This air is critical for all plants including grass.
Foot traffic causes compaction, which causes grass to grow poorly. The solution is to aerate the soil. This reduces compaction, allows more air to enter the soil and grass grows better. This is traditionally done with a mechanical device called a core aerator. Now companies are promoting liquid core aeration products to do the same thing.
What is Core Aeration?
A machine called a core aerator is run over the lawn as it pulls out short plugs of soil. It actually digs holes in the lawn and drops these cores on top of the lawn. Over the next week the cores slowly break apart and fill in the holes. The holes also allow the soil to expand sideways to fill the holes.
Core aeration is recommended by almost all government organizations, like the US extension offices and lawn research facilities, as the best way to reduce lawn compaction. It does work, at least for a short period of time. As people use the lawn it gets compacted again and the process needs to be repeated.
Why Do We Need Liquid Lawn Aeration?
A lawn care professional told me that people don’t want it done because of the mess it leaves. Customers think the remaining plugs are ugly. That is kind of silly because the cores disappear in a few days, but some people are very fussy about their lawn.
To do core aeration you have to either hire someone or rent a machine and do it yourself, both are costly and inconvenient. Enter DIY liquid aeration products. Just buy them and spray them on your lawn – job done.
The attraction to liquid aeration products is the convenience factor and the fact that you can do it yourself.
What Are Liquid Core Aeration Products?
That is a good question that is not easy to answer. The content of these products is not usually made public but the main ingredients can be a combination of a surfactant, humic acid and seaweed extract.
Surfactants are a type of soap. Lots of garden DIY mixtures include dish soap to help the liquids stick to plants and soil, and the surfactant in these products would do the same thing, making it easier for the product to soak into the soil.
The other products are food for soil microbes.
Liquid Core Aeration vs Liquid Soil Conditioners
There is another similar group of products called liquid soil conditioners. Based on ingredients, these products are the same as liquid core aerator products except they contain things like fertilizer, vitamins, plant growth hormones, and bio-stimulants. The claimed benefits of both products are very similar.
Benefits of Liquid Core Aeration Products
Almost all of the claims for these products center around the fact that they reduce compaction. Reduced compaction will do the following.
- Break up clay deeply
- Improve soil structure
- Bioactivate soil
- Increase water infiltration
- Increase air penetration
- Allow roots to grow deeper
There is no doubt that these are benefits of reduced compaction. But …. do these products really reduce compaction?
Some of these products also claim to reduce thatch. That is not surprising since the ingredients are similar to liquid thatch reducers, which I have discussed previously.
Do Liquid Aeration Products Reduce Compaction?
The claim is that by stimulating microbes, they will in turn reduce compaction. This will happen, but this process is a very slow process, taking many years, not weeks, as claimed for these products.
One popular product recommends applying “2 oz per 1,000 square feet”. Keep in mind that the 2 oz portion is 95% water, so you are spreading a pinch of organic matter over a very large area of soil. That will do nothing to stimulate microbial growth and it certainly won’t decrease compaction.
The Colorado Extension office says, “It is simply wishful thinking to believe that a highly diluted solution of either of these (surfactant or humic acid) applied to a compacted soil will in any way affect soil bulk density (i.e. compaction). There is no indication that ANY of these products has ever been scientifically evaluated for effectiveness.”
Nebraska extension says, “There is no evidence any of these products have been scientifically evaluated for effectiveness. Bottom line – its wishful thinking to believe such a solution will have any effect on compacted soil.”
A lab experiment using a commercial liquid organic polymer solution (a product similar to the ones being discussed here) found no effect on soil aggregation. This reference was used by a company promoting a liquid aeration product as evidence that their product worked.
Why would a company reference a negative study? Because most people won’t read the study!
When humic acid was added to putting greens they resulted in lower moisture levels suggesting the claims for better water infiltration are false.
Liquid Aeration products will have almost no effect on compaction, and therefore the benefits listed above are all false claims.
None of the products I looked at had scientific references showing that their products worked.
The theory is sound. Add organic matter to your lawn and it will stimulate microbes which in turn reduce compaction. But you have to add a lot of organic matter and the process is very slow.
If you really want to try and aerate your lawn this way, spread 1/4″ (0.6 cm) of compost over the whole lawn, each spring.
DIY Liquid Aeration Products
If there is a commercial product for it, people will develop homemade replacements. There are a number of homemade liquid aeration solutions being promoted. Some use diluted baby shampoo – that adds the soap part. Hydrogen peroxide is also used, but how can diluted 3% peroxide spread over a large area do anything? Some suggest just spreading dry humic acid which probably works as poorly as the liquids, unless you use a lot.
Lots of homemade lawn tonics contain all kinds of stuff from the kitchen. None of these are going to significantly reduce compaction.