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Best Fertilizer For Clay Soil Lawn: Why Ingredients Matter

Best Fertilizer For Clay Soil Lawn: Why Ingredients Matter

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Paul Brown

Growing a lawn in an area with high levels of clay in the soil is very challenging. I’ve been working my red clay soil for the past three years to nurture a thriving yard and have learned a lot. When it comes to fertilizing the grass in a clay soil environment, there are a few key points to keep in mind. But here’s the most important takeaway:

The best fertilizer for a clay soil lawn will promote deep root growth of grass while not negatively contributing to the abundance of nutrients that are already present. Examples include:

A common misconception is that clay soil is lacking in nutrients but the truth is that clay soil can hold significant amounts of nutrients (source).

The problem is the density of the soil – how tightly it binds together. It doesn’t allow the nutrients to be released. And so, to grow a hearty lawn, we have to look at the source of the issue and correct the underlying cause.

Keep in mind that we are working with two pivotal and interlinking conditions when growing a lawn:

Grass Type and Soil Properties

We can water, fertilize, and add soil amendments but how we choose to do this depends on the type of grass we are working with and the unique properties of the soil itself.

Let’s focus on the second part of this equation…

A Lawn Is Only As Healthy As The Soil It’s Grown In

We know that the quality of soil dictates the quality of our lawn. Yet, we often fail to really consider how clay soil impacts the lawn beyond the obvious: It gets hard as a rock when it’s dry and soggy when it’s wet, right?

But there are so many other issues that we need to understand so that we apply the right type of fertilizer and prevent making things even worse!

Clay Soil Holds Onto More Than Nutrients

Clay soil not only retains beneficial nutrients, it also holds onto dangerous chemicals that are spread onto your lawn like pesticides (source).

This means that season after season as you are spreading chemicals to eliminate weeds, kill insects, and other lawn invaders, the clay soil is potentially capturing and retaining these chemicals allowing for a gradual buildup of toxic properties within the soil.

While aimed at getting rid of pests, many chemicals actually impact the growth of beneficial microbial activity. Your soil desperately needs these microbes to improve the quality and texture of the soil and to provide benefit to your lawn.

So you see, it’s a bit of a catch 22.

We put all of these toxic chemicals out to prevent the things we don’t want but we end up poisoning the ones we do. And with clay soil and it’s impressive ability to hold onto those toxins, it can create a compounding effect that can have a horrible impact on your lawn over time.

While everyone should be concerned about the chemicals they are putting on their lawn, those of us with clay soil lawns need to be particularly mindful of the impact of our actions.

And so, it’s time to rethink lawn care for growing in heavy clay soils.

A simple soil test (link to Amazon) will provide definitive information on which nutrients are lacking and how to best fertilize your clay soil lawn.

Improve A Clay Soil Lawn By Encouraging Microbial Activity

When soil is healthy it is alive with microbial activity. Beneficial organisms devouring and depositing organic matter, creating an ecosystem where your grass can thrive.

If you want healthy grass, you need to make sure that you are encouraging beneficial microbes so that you can have healthy soil.

We do this in a number of ways including core aeration, ensuring proper pH, and of course wise lawn fertilization options. None of these is a one-and-done solution. They work together to synergistically improve the overall quality of the soil and lawn.

Recommended Reading: Improve Clay Soil for New Or Existing Lawns

Use A Fertilizer That Feeds The Soil As Well As The Grass

To improve a clay soil lawn, we want to use ingredients that will encourage the grass to grow greener and push its feed roots deeper while at the same time, benefiting the microbial ecosystem in our soil.

Fortunately, there are plenty of natural lawn fertilizers that we can select from.

Scotts Natural Lawn Food

Many homeowners don’t realize that Scotts makes a fertilizer that is made from natural ingredients. It can be used anytime throughout the year and is pet and kid-safe.

There’s no required “Stay off the lawn for xx hours” issue with this meaning you can immediately turn the kids and pets loose in the yard.

Scotts uses solutions including blood meal and meat meal in addition to potash (a source for potassium).

Click here for the latest pricing and availability (Link to Home Depot)

GreenView Turf Nurture

Listed as a natural lawn restoration formula, Greenview’s Turf Nuture lists ingredients including soy protein, meat and bone meal, and potasium sulfate, all of which are natural fertilizer solutions.

Greenview advertises their fertilizer as pet and kid safe when used as directed.

Check current pricing for Greentree Turf Nurture (link to Amazon)

Sunday Lawn Care

I’ve taken interest in the natural lawn care solution offered by Sunday lately. Instead of a one-size-fits-all prepackaged solution, this company individualizes the ingredients and quantities based on the customer’s soil type. (Click here for my detailed review).

They begin with a general solution defined by your physical address which provides some level of insight into the soil makeup of your region. With your first application, they include a soil test kit.

When you send in your soil sample, they evaluate the specific needs of your soil and adjust future applications as appropriate.

This means that you are feeding your lawn the specific amounts of nutrients needed to enrich your soil.

Granted, you can do this yourself by mixing and matching different applications of fertilizers in varying quantities to meet your soil’s needs but having it handled for you is quite a pleasant auto-drive approach.

Sunday uses natural ingredients including seaweed, iron, molasses, and soy protein. They also include micronutrients, potassium, phosphorous, and other natural beneficial solutions.

Instead of a buy-as-you-go approach, the company offers a subscription program so that they can anticipate and customize each application based on your lawn’s needs.

It’s an innovative solution for the homeowner that takes the guesswork out of feeding your grass and soil.

Learn more about Sunday Lawn Care (link to Sunday’s website)

But What About The Weeds & Insects?

If we eliminate the chemicals that kill weeds and insects, don’t we create an environment that promotes overgrowth and invasion?

It’s a fair question and the answer takes a little explanation.

First of all, understand that a healthy lawn will often choke out many of the unwanted weeds from your lawn. For example, I stopped applying pre-emergent weed killer a couple of years ago. At the beginning of the season, my yard gives every indication that I am in for a tough spring.

This is what my lawn was looking like in February before the grass began actively growing. No pre-emergent applied.
Weeds forming in February

But by fertilizing using natural ingredients combined with frequent mowing practices, I manage to choke the weeds out and pretty much keep them out for the whole season. Clay soil or not, I’m determined to have a thriving lawn!

Clay soil lawn fertilized but no pre-emergent applied.
Late May with no pre-emergent used

It’s not perfect yet and I am still dealing with some clusters of clovers here and there but by and large the lawn is coming along nicely. I’ve applied nothing except my first application of Sunday Lawn Care.

Now, when you do have those pesky weeds that just won’t choke out, you have a couple of options. You can use a natural weed inhibitor like Natural Armor Weed and Grass Killer (link to Amazon).

The only problem is that it kills the grass too. This is fine for certain applications but in the middle of a lawn, you are going to want something more specific in it’s targeting.

Sunday offers a weed killer called Dandelion Doom (2 bottles) – $24.00 that contains only iron as it’s active ingredient. They report that it will kill most broadleaf weeds without harming the lawn. A natural solution to an age-old problem.

The bottom line is that we do have options. We just need to be a little smarter in how we go about dealing with those weeds.

And the same holds true for insects.

I used to use a lot of insecticide sprays and granules all over my yard to keep fire ants under control. With clay soil, there are good reasons not to kill ants, but fire ants that are too close to the house or in areas where children play have to be controlled.

I’ve never found a natural solution that works, at least not yet, and so I tend to apply Amdro Fire Ant killer directly around the mound instead of spreading poisons all over the yard. This way the beneficial microbes throughout most of the soil are unaffected.

Again, precision targeting vs broadcast spreading. I think that’s the most sensible approach so that we don’t disturb the natural development of microbial activity in the soil.


There’s no perfect solution but fertilizing a clay soil lawn using natural ingredients instead of toxic chemicals that can build up over time in the soil is a huge first step to growing a healthy lawn in what is admittedly difficult soil.

Consider the long term implications of the fertilizer you are currently using and ask yourself this: “Will this encourage or inhibit beneficial microbial activity?” The answer to that question will likely guide you well in choosing the best fertilizer for your clay soil lawn.

Recommended Reading: Amend Clay Soil Without Digging – 5 Steps To Lasting Results