Clay soil is a big challenge when it comes to growing grass. It’s dense, holds water, and these characteristics make it prone to getting compacted over time. Compact soil is not welcoming to grass because it is challenging for root growth. It also prevents adequate drainage, and doesn’t allow enough oxygen to get into the root zone. To break down clay soil quickly, there are several methods you can use.
Aerating clay soils is the most effective and proven way to break down the clay. It allows for the roots of your lawn and garden plants to penetrate deeper into the soil.
Unfortunately, there is some misinformation on this topic that can lead homeowners astray.
In this article, I will be exploring some of these myths and misconceptions. I’ll also share some of the proven remedies for clay soils that are compacted. These are techniques I’ve personally used to address dense clay soil.
This is a very common issue for lawn owners. Luckily, it’s something you can address on your own if you don’t mind some DIY projects.
Understanding the Challenges of Clay Soil
Clay soils contain very small particles that are tightly compacted together. This is why it’s difficult for water to penetrate them.
As a result, you may often have areas of standing water on your lawn, a lack of oxygen reaching the roots, and stunted growth because of a lack of nutrients.
Clay soils are caused by weathering of bedrock over thousands of years and are formed by the action of wind, water, glaciers, and other forms of erosion. Clay soils are common in areas with a history of heavy rainfall or glacial activity.
These factors lead to the rocks that make up soil becoming finer and, therefore, more densely packed together, which makes it difficult for water, air, and nutrients to penetrate the soil.
It’s important to note that you can amend clay soils to improve the soil structure, and there are a variety of methods for doing this (I’ll get into these in a moment).
If you have clay soil, you’ll probably notice problem areas near paths and where people or pets walk regularly. Heavy foot traffic is one of the main cause of clay soils becoming compacted and hard. That’s because when you walk on soil, it compresses the particles together – making a bad situation worse.
Not only is foot traffic a leading cause of clay-type soils becoming more compacted over time but so is poor irrigation as pooling of water leads to particles flowing and compacting together. So grading your yard properly and improving how water flows across your land can improve things for you.
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Common Misconceptions About Resolving Issues With Clay Soils
The two recommendations you’ll find online that get it wrong concern:
Gypsum has some degree of effectiveness with clay soils, as it does add calcium to the soil and this can improve drainage.
However, the idea that adding gypsum alone can break down clay soil is a myth – one you may have read about or heard.
I recently wrote about how the real benefit of applying Gypsum to your lawn is to address issues with high soil salinity. High salt levels in soil can sometimes present in a similar way to dense clay soil, and helping the salt move out of the topsoil with a Gypsum application can improve the soil’s structure and drainage if that’s what’s going on in your yard’s soil chemistry.
But Gypsum isn’t doing anything specifically for your clay issue.
Another misconception about clay soils is the idea that doing a lot of cultivation and using a rototiller will help to break them down.
While this may sometimes work, the process of cultivating the soil can actually make some clay soils very thin and dusty. This, in turn, can make them more prone to erosion and compaction (in other words, the short-term benefits you’re seeing are probably causing long-term issues).
Cultivating may seem effective at first when treating clay soils. However, overdoing it can be very detrimental to your lawn and cause a lot of problems down the track.
How to Break Down Clay Soil Quickly
Aerating your soil with mechanical methods is a very effective way to ensure that your soil is properly aerated and that water, oxygen, and nutrients can penetrate it.
Mechanically aerating your soil involves the use of a machine that penetrates the top layer with spikes or blades to create small holes in the soil.
When it comes to clay soils, it’s important to make sure you do aeration the right way. If you do it improperly, your soil could end up even more compacted.
If you do it correctly, however, mechanical aeration can be very beneficial to clay soils. It will allow for better root growth and healthy grass or plant life above ground.
After mechanically aerating your soil, it’s important to avoid any foot traffic on the areas you’ve treated. This can instantly undo all the good work you’ve done and cause more compaction.
So, make sure you wait a while before walking on your lawn after doing aeration on clay soil.
Different Kinds of Mechanical Aeration
The two main kinds of mechanical aeration are spike and plug/core aeration.
With spike aeration, you use a spike aerator to put holes into the soil. This is an effective way of aerating with many soil types, but with clay soil, it’s not what I recommend.
That is because already existing compaction can get worse around the holes from spike aerators.
I recommend that you consider using a core aerator (sometimes called a plug aerator).
A core/plug aerator actually removes plugs of your soil, creating much bigger holes. This creates more room for nutrients and water to get down into the soil.
For extremely heavy clay, I also recommend topdressing with some compost or something else after aeration. Allowing this soil amendment to fall into the holes each time you aerate can, over time, improve the structure of your topsoil.
How To Break Down Clay Soil Fast: Liquid Aeration
Liquid aeration is a very popular method for breaking down compacted clay soils.
Liquid aeration is a process where you apply a liquid solution to the soil, and it helps break down the clay particles and create more pockets of air in the soil. This makes it easier for water, oxygen, and nutrients to get down into the soil and to your lawn’s roots.
Does it Really Work?
How effective liquid aeration is depends on the type of products used and how often you apply them. There are conflicting views about its efficacy in the industry.
According to Stuart Franklin, the founder and President of Nature’s Lawn & Garden, liquid aeration is very effective. “Our lawn care service has been doing liquid aeration instead of core aeration on our clay-based lawns since 2002. It is faster, and easier to do,” he says, “there’s no mess or risk of damage to property tree roots, and it aerates more completely and deeper than plugs can.”
Jeremy Yamaguchi, CEO of Lawn Love, disagrees. “I typically don’t advise using liquid aeration because it’s not as effective as actually physically breaking apart the soil,” he says.
My first-hand experience is inconclusive. I’ve tried Aerify Plus via a hose end sprayer. I liked using it, and the lawn responded well, but I didn’t have a compaction problem to begin with so I can’t say how well it works.
Maybe it’s hard to teach an old Lawn Chick new tricks, but I’ll continue to mechanically core aerate my yard.
Things to Know Before You Try It
Based on everything I’ve seen and read, I’d say that compared to mechanical aeration, liquid aeration takes a bit longer to work and often requires multiple applications.
The benefit of using a liquid aerator is that it gives better coverage. Unfortunately, however, it doesn’t create the kind of immediate results you get with mechanical aeration.
Also, liquid aeration can be a little more expensive than mechanical aeration. That is because you usually need to use liquid aeration products over long periods.
If you decide to use a liquid aerator, be careful not to over-apply your chosen product. It might be very damaging if you use too much.
If you do try one of these products, choose something that contains nutritional ingredients, such as humic acid, seaweed, and kelp, to make your lawn healthier.
Once you’ve aerated your clay soil, it’s a good idea to implement some long-term solutions to help prevent the soil from getting compacted again.
How? Well, I’ve found one of the most effective ways to do this is by establishing a good level of organic matter in your soil.
I’m going to talk about the benefits of organic matter when it comes to improving clay soils below.
The Benefits of Adding Organic Matter To Improve Clay Soils
Once you’ve aerated your clay soils, adding organic matter to the area is a great way to ensure that it stays loose and does not compact again.
Organic matter helps to create a good environment for microorganisms that help break down the clay particles and keep them from sticking together.
It also helps with retaining moisture in the soil so that plants can get the water they need while also reducing compaction due to foot traffic.
Organic matter also helps improve your clay soils by providing a lot of valuable nutrients for plant growth, which can be beneficial if you’re planning on doing any gardening in the area.
Adding organic matter to your clay soil doesn’t take too much time or effort, and you can do it with a few simple steps.
My preferred method is to add a thin, 1/4″ layer of screened compost as a top-dressing to my lawn when I core aerate it. I do this annually or bi-annually while overseeding my lawn in what I like to call my “big project weekend” in the fall.
Once your lawn and garden have deep roots established in your soil, clay soil compaction is very unlikely to occur again unless irrigation issues persist or if the plants start to decline.
It’s important to keep in mind that adding organic matter to clay soils takes some time for it to be fully effective, so don’t expect results immediately.
The Truth About Tilling Sand In Clay Soils
It’s a big mistake to till sand into your clay soil. Some homeowners believe it’ll help break the soil up, but in my experience the opposite is true.
In fact, doing this can do more harm than good.
In other words, tilling sand into clay sand may make your compaction problem worse. This is because it will create more solid particles that don’t allow water, oxygen, or nutrients to penetrate the soil.
This can create an environment where plants don’t get enough access to all of the things they need to survive and thrive, and compaction can become an even bigger issue.
Is Rototilling Good for Breaking Up Hardpack or Sticky Clays?
If you’re starting a new lawn from scratch and don’t have any grass in your soil yet, you could consider using rototilling to help break up compaction.
However, you probably shouldn’t use this method if you already have established grass, as it will destroy it. But if you’re willing to re-plant new grass, however, this is a viable option.
The biggest advantage of rototilling is when you are using it to incorporate organic matter into your soil. When you rototill, it helps to break up the clay particles and allows for better drainage of water and oxygen into the soil.
You can hire a rototiller from a local machine shop or lawn care center, so don’t worry about having to buy one.
Wherever you get your tiller, the type you use matters, according to Arthur Davidson, a horticulturist and member of Lawn Chick’s Expert Panel. “If you’re going to till, use a tiller with spike tines,” he says. “Bolo tine tillers can compact the soil because the bottom of the tines are parallel to the ground. If you have to use a bolo tine tiller, find one with rear tines. Rear tine tillers make a much finer soil and seed bed.”
Additional Tips for Success
Rototilling can be tricky, especially your first time. It’s easy to over-till the area and create a clumpy mess where plants won’t thrive. You also need to be careful as these machines are powerful.
I advise that first, you make sure you understand what type of soil you have.
Next, you need to know how much tilling you need before even considering using this option.
Finally, after you’ve aerated your soil through mechanical aeration, chemical aeration, or rototilling, it’s a good idea to test your soil. This will help you to establish what you need to do to get it ready for the grass or plant life.
A good lab-based soil test kit for your lawn will tell you how much organic matter is present. This way you’ll understand how much amending you should plan to do. It will also identify any other soil issues (like high salt content) that can be addressed to improve drainage.
Testing Your Lawn or Garden’s pH Levels To Help Make Clay Soil More Habitable
Because of the compaction in your clay soil, a lot of essential nutrients and acidity can be lost due to the poor flow of oxygen and water.
This can make it harder for plants to survive and stay healthy in the soil.
The Lawn Chick editorial team regularly interviews industry experts to bring our readers the latest science and expert recommendations to complement our own hands-on lawn care experience.
We Asked: How does soil pH impact a lawn’s ability to utilize the fertilizer you apply and the nutrients available in your yard’s soil?
Teri Answered: “Soil pH is a crucial indicator of soil acidity, and tells us if your yard has the ideal pH for the plants (like grass) you’re growing. It also impacts how well grass utilizes applied fertilizer and absorbs soil nutrients. The sweet spot for lawn pH is between 6.5 and 7.0, but most lawns are adaptable, typically ranging from pH 4.0 to 9.0.”
“If your lawn is thriving but the pH isn’t in the ideal range, there’s no need to adjust it. It’s typically difficult to adjust pH levels, but if pH is too high, you can try adding organic matter like compost, and if it’s too low, applying lime can help.”
Natural Science Manager at Sunday
At Sunday, Teri leverages data analysis, lawn and garden industry trends, and customer needs to create impactful content. With a combination of her conservation background and expertise in science communication and content strategy, Teri works to advance sustainable yard care practices on behalf of Sunday.
I recommend that homeowners test their yard’s soil at the beginning of each season.
This helps you understand your baseline and game-plan what you need to do (if anything) to support your grass health during the growing season ahead.
The most direct way to do this is by using an at-home lawn soil testing kit which will allow you to find out which nutrients are missing from your soil and its pH level.
Best Overall Lawn Soil Test Kit
The Soil Test Kit I Use & Recommend
There are many options for testing your lawn’s soil, but I prefer a lab-based soil test that provides a detailed analysis of your soil’s nutrients and what’s needed for your lawn to thrive.
I use this one from MySoil every year.
And if you’re interested in taking the guesswork out of what to do next after you get your soil test results, consider Sunday’s subscription lawn-care plan. They test your soil for you and use local weather data to send you exactly what your lawn needs, when it needs it. It’s pretty fool-proof – you can Click Here for Your Instant Lawn Analysis and take 15% off your order with promo code LAWNCHICK2024.
After testing, you’ll understand what is needed to make your clay soil better able to grow and sustain a healthy lawn. Then you can start working on adding nutrient-rich material such as compost or manure to help build up the soil again.
Final Thoughts: How to Break Down Clay Soil Fast
Once you have broken down and aerated your clay soil, it’s important to keep any future compaction at bay.
An important part of this is regularly aerating your soil. This is key to preventing and alleviating compaction. If you have clay soil on your property, I recommend annual aeration as part of your yearly lawn care schedule.
When you tackle this project, overseed your lawn with grass that’s well suited to your growing zone, and top-dress with organic matter once annually, and you’ll be on your way to a beautiful, healthy lawn.
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