How to grow or fix a lawn with clay soil.

A lawn with clay soil can be a difficult contender.

As a rule of thumb – your topsoil is the top 6 inches of your soil.

If you are not positive that this is part of the problem with your lawn, you can do a soil test. You can pick up a kit from a local garden centre or send a soil sample to a lab.  

Typical problems that hinder a good lawn due to high clay content may include:

• Water pooling;

WHY:  Clay becomes very compact over time and has poor drainage.

• Lack of moisture in dryer months;

WHY: Water does not penetrate easily into soil with a heavy clay content and becomes extremely dry in the summer months.

• Shallow root system;

WHY: Clay can be hard for roots to penetrate if compacted. Because of the lack of water penetration roots my not search for water, and just hang out near the surface.

• Weeds thriving more than grass;

WHY: Many weeds can thrive in areas where grass may struggle. Lack of proper nutrients, as well as oxygen and water to the root system can cause grass to die or become diseased, at which point weeds have the freedom to move in and take over.

• Lumpiness;

WHY: Because clay compacts and becomes very hard in the summer months and does not have the flexibility to even itself out as much as a lawn with a higher organic matter component.

Just as using the right type of grass seed, proper fertilization and soil treatments is important, so is the amount of clay in your soil.

What causes high clay content?

It could be as simple as the soil where you live is primarily clay.

Unfortunately, many times when homes are built the topsoil is removed or buried under clay that is dug up when laying the foundation. Rolls of sod are then laid on top of that now primarily clay soil, and once the nutrients are used up in the sod itself everything begins to go awry.

How do I fix a lawn with high clay content?

An ideal organic content in a lawn is generally considered to be 5% – 6%. For more details on just how much soil you may need to add there is a good article here: https://www.lawn-care-academy.com/clay-soil.html

No existing lawn (New Build)

If you bought a new house, you may have the opportunity to decide whether they will put in a lawn for you or not.

1. If there is in fact too much clay you can add high-quality topsoil and plant a new lawn or, if you are not able to raise the height of the lawn or have weeds growing there already, you may need to remove some of the existing soil and rototill in the new topsoil to lower the clay content.
2. Heavily seed the newly laid soil with the appropriate seed mix for your climate zone.
3. Add a quarter-inch of topsoil over the seed to help retain moisture and protect the seeds through the germination process. You can use a shovel and the back side of a metal rake to spread the topsoil.
4. Add fertilizer that will help new growth such as a 16-32-6.
5. Add lime if the pH still needs correction.
6. Water for 15 – 20 days depending on the germination rate of the seeds, keeping the soil moist. About 15 – 20 minutes per day in most cases.

Ripping out an existing lawn

If you have bought a house with a lawn that you feel is too far gone for repair or have not maintained in so long that it has now deteriorated to this state you may have to take out the top few inches of soil.

1. You can dig out the top 3 or 4 inches of soil or whatever is necessary to remove the root systems of the weeds and plants that are growing there and replace all or, ensuring that you are allowed to raise the level of your lawn, add 4 – 6 inches of new topsoil to the property.
2. Heavily seed the newly laid soil with the appropriate seed mix for your climate zone.
3. Apply a quarter-inch of topsoil over the seed to help retain moisture and protect the seeds through the germination process.
4. Add fertilizer that will help new growth such as a 16-32-6.
5. Add lime if the pH still needs correction.
6. Water for 15 – 20 days depending on the germination rate of the seeds, keeping the soil moist. About 15 – 20 minutes per day in most cases.

Modifying an existing lawn

Your lawn may have too much clay and be in a rough state, but you are willing to work with it over time to get it where it should be. This is also the least labour intensive and the most cost-effective option in most cases.

1. Power rake if necessary. (Excess moss and thatch build-up)
2. Aerate every spring and fall, and remove the cores as they are primarily clay (at least the first few years probably).
3. After aerating, over-seed the lawn with the appropriate seed mix for your climate zone.
4. Apply a quarter-inch of topsoil over the seed to help retain moisture and protect the seeds through the germination process.
5. Add fertilizer that will help new growth such as a 16-32-6.
6. Add lime if the pH needs correction.
7. Water for 15 – 20 days depending on the germination rate of the seeds, keeping the soil moist. About 15 – 20 minutes per day in most cases.
8. Repeat 2 times per year.
9. Tip: Leave your lawn clippings on the lawn when you mow (assuming you mow regularly) and they will help to add organic matter to the lawn over time as well.

For more info on grass seeds: http://mylawn.care/2019/05/15/what-do-different-types-of-grass-seeds-do/

For more info on climate zones: http://mylawn.care/2019/05/22/why-are-provinces-and-climate-zones-a-factor-in-planting-or-maintaining-a-lawn/

We at MyLawn.Care have taken all of this into account and blended lawn Care Packs specifically to perform in the BC lower mainland, so that you do not need to worry about this and can just add topsoil, spread the Care Pack and enjoy the results!

If you would like to hear more on another topic, or have any questions on the above, feel free to comment below or email us at [email protected]. We are here to help!