How to Improve Clay Soil for Lawns [Grow Grass in Clay Soil]

Clay soils are densely compacted therefore quickly becomes waterlogged in wet weather and too hard when they dry out. This makes it impossible for important nutrients air and water to reach the grass roots. It makes a lot of sense if we look at how to improve clay soil for lawns.

How to Improve Clay Soil for Lawns

Apart from causing stunted growth of grass, clay soil leads to the problem of standing water in yard, growth of moss in lawns, bad smell in the yard and unhealthy playing areas for kids and pets. Clay soil in lawn can be improved through a number of ways.

Lawn aeration

During core aeration, a lawn aerator with hollow tines mechanically removes plugs of soil and thatch from a lawn. This creates a channel through which air, water and nutrients will penetrate the soil to reach the grass roots. Aeration should be done when clay soil is relatively dry.

Apart from the traditional ways of aerating a lawn, liquid aeration is a new technique of loosening up compacted soil without pocking holes. A liquid solution is simply applied on the lawn to create entry ways for water, air nutrients.

While it sounds like an effortless way of improving clay soil, turf grass experts explain that the method may not effectively work on heavily compacted soil. Similarly, spike aeration is said to help less in breaking soil compaction.

Annual aeration is recommended for lawns with heavy clay soils. However, without proper timing, the process can stress the grass. You should never aerate grass that is dormant.

Early fall or early spring is the best time to aerate cool-season lawn grasses while late spring or early summer is suitable for warm season grasses. Once done, this will be the best time to overseed and fertilize your lawn.

You can hire lawn aeration service from a nearby lawn care professionals or hire the equipment from a rental company. However, core aeration is not the ultimate solution to the problem of clay soil in your lawn but a very important start for other soil amendments.

Top dressing

Topdressing can help in breaking down the clay soil in your lawn. Once you have done aeration, take a well decomposed composed and apply a thin layer of 1/4 inch to 1/2 inch. Then use the back of a rake to work the material into the grass.

Addition of organic matter on topsoil greatly improves the soil structure, enhance water retention capacity, reduce thatch and introduce beneficial soil microbes. Topdressing should be done in fall for cool season grasses and in spring for warm season grasses.

Before you top dress a lawn, mow the grass as short as possible and run a core aerator. Next, remove the plugs of soil extracted and apply a well-decomposed compost. Work in small sections, and ensure every part of the lawn is thoroughly covered.

Topdressing may take several years to completely improve your lawn’s clay soil. If done correctly you will see improvements in drainage, water retention and overall health of your grass.

Prevent heavy traffic

Heavy traffic on your lawn can ruin efforts and chances of improving the clay soil. Children and pets playing in the yard, walking or driving on the lawn are among activities that will compact the soil and reverse any efforts of improving your clay soil.

You should therefore try to minimize any form of traffic on your lawn while undertaking any clay soil amendments.

What to avoid

Some people will think that adding some sand to clay soil will make it better. This is very far away from the truth. Sand will make clay soil even harder especially during summer or in drought conditions. This will make it even impossible for water and nutrients to percolate the soil.

Avoid mowing your lawn short as this will make the clay soil to dry out. Mowing high especially during summer or drought will help the clay soil to remain cooler and therefore less watering will be needed.

After mowing, you should also leave the grass clippings on the lawn to provide mulch and also nutrients to the grass once the clippings decompose.

How to grow grass in clay soil

Having clay soil in your yard is not the end of the road for your dream of having a green lush lawn. You can successfully grow grass in clay soil. Here is what it takes:

1. Test for clay content in the soil

If you are starting a new lawn from scratch, you should always begin by conducting soil tests. To know the type of soil you are dealing with, you can use the Mud Shake Test as explained by gardeners.com or simply scoop a small amount of the soil and mix with little amount of water and kneed it in your hand.

Clay soil will feel sticky in your hand and when you press it between the thumb and your index finger it will form a ribbon longer than 1 inch. This means that you have to initiate clay soil amendments before you plant any grass.

2. Turn over the soil

This is one of the initial amendment to undertake as a way of improving clay soil for lawns. Digging dipper breaks the soil compaction for proper penetration and development of plant roots. Run a rototiller over the area you want to grow grass. You can rent a rototiller in any nearby gardening center.

3. Apply compost

Once you have turned over the soil, spread compost several inches thick over the entire area. Once done, go over the area again with a rototiller to work the compost into the soil. You may do this several times as long as you have enough compost to apply. Once done, rake the soil to remove rocks and any large debris.

Apart from improving the structure of clay soil for better growth of plant, a well-decomposed compost adds organic matter that enriches the soil, retain soil moisture, lower the soil pH and reduces the need for chemical fertilizers.

4. Choose the right grass for clay soil

Several grass species adapts well in clay soil. They are the kind that will give you an easy start and few problem under different weather conditions. The following are best grass for clay soils.

Tall Fescue

Tall fescue grass is a cool season grass that does well in clay soil. It has a deep root system that makes it to stand up well to drought, heat and cold conditions. Tall fescue will offer a dense thick lawn in almost all soil types thus the best for your clay soil if you come from the cold northern regions of the US.

Bermuda grass

For those in the southern warmer region of the US, Bermuda grass is the perfect choice for your clay soil. This type of warm season grass produces deep rhizomes which makes it to thrive in clay soil and drought conditions. As long as you keep your lawn well fed, Bermuda grass will spread faster and fill any bare spots.

5. Proper lawn care

Once you have spread the seed, a proper lawn care program should follow. It should include the following:

Adequate Watering

Once you have planted your new grass, watering should be done but once or twice per day but without oversaturating the soil. Once the grass is established, water your lawn deeply but not too often to promote deeper growth grass roots. About 1 inch of water once per week will keep clay soil well-moistened.

High mowing

Mowing your lawn high is recommended for clay soil lawns. It helps in keeping the soil moist and also enhancing healthy growth of the grass. Ideally, cut your grass to a height of 6 to 8 centimeters. After mowing, leave the grass clippings to decompose on your lawn.

Proper feeding

In most cases, feed your lawn with compost. Apart from providing nutrients, a well decomposed compost will improve clay soil structure for proper penetration of grass roots. Compost also prevents soil compaction which makes roots to access air, water and nutrients.

Lawn aeration

If your clay soil is heavy, consider aerating your lawn once every year. Lawn aeration helps in breaking down the compacted soil for free flow of air, moisture and nutrients. Core aeration is recommended for clay soil as compared to spike aeration.

Reduce foot traffic

Heavy foot traffic contributes to soil compaction. You’ll want to keep kids and pets off the lawn for grass to thrive. You may replace grass with stepping stones in heavy traffic areas.

Control pest and weeds

Inspect your lawn for pests and diseases and provide appropriate treatment. Be sure to read and follow manufacturer’s instructions when using pesticides or any chemical weed control treatment on your lawn. You may also seek the service of pest control agencies.

Final Thought

It is possible to grow a thick dense lawn in clay soil if you carry out the required soil amendments and apply a proper care program for your grass. It may not take one season to get the results you want but with determination you will still achieve the goal.

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