A lawn with clay soil is heavy and compact and a pain to work on, especially when it’s wet. It will absorb and trap water for a long period which will make it difficult for your grass to get well established. When clay soil dries out, it becomes hard and restricts drainage and the amount of oxygen that will reach the roots.
However, with all these problems, clay soil has its benefits. It not only can hold in nutrients that your grass needs, but also hold moisture better than other soil types. With some amendments like incorporating organic matter, you can easily improve clay soil and turn this sticky clay into hums-rich soil that is fertile enough to support a beautiful lawn.
What is clay soil?
This is soil that is made up of very fine mineral particles that are heavy and dense that hold onto water instead of letting it drain off. Clay soil doesn’t have many organic particles like loam soil and is very compact which makes it hard for plant roots to get well established. When it comes to your lawn, not all grass seeds can grow in clay soil.
Amending clay soil
It’s possible to improve the condition of clay soil to allow you to grow a thick, healthy, and green lawn. Adding organic matter like organic compost, composted leaves, pine bark, and gypsum to clay soil can help to improve its structure and help to remove its compaction and drainage problems. Organic matter will also add nutrients, lighten the soil’s texture, moderate the soil’s temperature, improve drainage and aeration, and provide pore space that is important for plants to grow.
As a general rule if possible, add 3-6 inches of organic matter to your soil before planting and mix it with the top 10-12 inches soil where the roots grow. In the next years keep adding a top dressing of 1-3 inches of organic matter each year and as it decomposes it helps to improve the clay soil.
Steps to improve clay soil by applying organic matter
- Before you start adding organic matter, you need to first have a soil test done to determine the amount of nitrogen, potassium, phosphorous and other nutrients lacking in the soil. You can ask your county’s extension office for assistance in testing the soil or get a soil test kit.
- Aerate clay soil regularly to allow oxygen and water to freely move through the soil. It also helps to remove plugs of dirt from your lawn and break up the soil which allows the grassroots to spread. Aerate when the ground thaws when the soil is moist during the growing season. It’s best to aerate warm season grasses in early summer and cool-season grasses in early spring or fall and late spring.
- Use a tiller if your yard is large or a spade if it’s a small lawn to loosen the existing soil. Spread about 2 inches of the organic matter on top of the tilled area and mix it well and repeat this process twice. Ensure that the clay soil is relatively dry because working with wet clay soil can seriously damage its structure that you’re working to improve. The best time to do this job is during autumn when it’s drier than springtime and it’s a bit cooler.
- Install a drainage system because clay soil grains slowly and can easily get saturated, especially when there are heavy rains or snow. A lawn drainage system will help to transfer the water from one area to another using pipe or tiles like a waterway or man-made bed.
- Overseed in the fall when the grass has aged and dried up. Mow your lawn using the lowest setting then rake thoroughly as this will allow the seeds to fall closer to the soil which will give them a better chance of taking hold. Use your hands to spread the seeds or a push spreader, then water and cover with straw to prevent birds from snacking on your seeds. Seed again in early to mid-spring.
- In the long term, regular application of manure, compost, and other organic matter will continue to improve the tilth, structure, and overall health of your soil. This will make it easier to work in and easier for your plant to take root. Choose grasses that are naturally adapted to growing in clay soil to give your lawn a better chance of flourishing.
- Stay off your lawn because clay soil will eventually compact, especially in areas with heavy foot traffic. Also, avoid excessive mowing and rough playing when the ground is wet. You can install a sidewalk, lay stepping stones, or make a path near the entrances and your kid’s play areas to avoid stepping on your lawn.
- Mulch your lawn regularly. Leaving grass clippings and leaves on your grass will allow them to decompose and provide nutrients to the soil and also attract friendly earthworms that snack on the mulch and fertilize the soil as they move through it.
- Water the soil deeply and infrequently because clay soil has a problem with shallow grassroots and light shallow watering will cause the roots to reach upwards in search of water. Use a sprinkler with a timer to water your lawn 1 inch per week.
Things you shouldn’t do
While mulching is great, mulching too many at once isn’t. Don’t try to mulch a thick layer of bur oak leaves instead mulch it a bit at a time or bag some. Leaves from the silver maple trees can be turned into the dust which means you can use large amounts for mulching.
- Don’t add sand into your clay soil as it will turn it concrete-like soil.
- Don’t mow your lawn short because dry soil will result in rock hard soil that isn’t good for your lawn grass.
- Don’t add wood chips to your lawn because they drain the nitrogen from the soil when they decompose.
- Don’t allow your clay soil to dry out because it will become extremely hard and this will make it harder for water and nutrients to get through down into the soil. Keep it moist even during the dry season.
Gypsum is very easy to apply to the soil surface with the help of a lawn spreader.
It’s a great way of improving relieving compaction, increases water penetration, improves drainage, correct soil conditions to allow for better plant root growth, and improving the soil structure in your existing lawn.
Gypsum also adds essential plant nutrients like sulfur and calcium to your soil without affecting its pH. By adding gypsum to your lawn or vegetable garden, it will help to prevent calcium deficiency which is the main cause of blossom end rot disease.
Grass seeds for clay soil
Knowing the best grass seeds to plant in your lawn will depend on whether you live in a warm or cool climate. If you live in a warmer climate, you’ll need grass seeds that can thrive in the heat or if you live in the cooler climate, you’ll need grasses that can do well even in extreme cold.
How to choose grass seed for clay soil
Type of seeds
This will depend on the kind of grass you want to plant if it’s one type to give you a uniform look like a golf course or a mixture of different grasses if you need the benefits for all. Most people like mixed grass seeds that will give you features like drought-tolerant, durability, insect protection, and many others in one.
It’s very important to purchase grass seasons according to the season for better results. You can choose cool or warm season grass seeds depending on the climate in your area. Warm-season grasses can tolerate high heat and are drought resistant and are best planted in early Spring. The cool-season grasses can tolerate extremely cool temperatures and can grow even in snow and are best planted in Fall.
Most homeowners worry about how much traffic their grass can handle, especially if you have kids and pets who love to play on the lawn. Look for grass that is high traffic resistant.
Types of grass seeds
Grows quickly, can handle heavy traffic, low maintenance and has robust roots
Spreads horizontally across the ground using stolons, holds well against pests and is low maintenance
St. Augustine grass
Course and tough with wide blades and can tolerate drought and extreme heat
Soil with some sand
Fast-growing, very thin pointed leaves, mostly used in seed mixes, can’t endure long periods of heat and dry weather and does well in full sun and shade
If you live in colder climates or up north, cool-season grasses are the best option for your lawn because they thrive when it’s colder outside, especially during autumn and spring, and also adapt and survive even harsh winters.
These grasses become dormant when it’s hot outside during the summer season. The best cold season grass is tall fescue because it can handle dense clay soil very well and it has a reliable root system. Its deep roots allow it to handle the heat and low water conditions.
These grasses thrive in hotter climates, especially during the summer, and become dormant when the weather becomes cool.
Warm-season grasses can’t tolerate the cold very well and grasses like Zoysia will do well in clay soil because of its robust root system which can grow through dense soil.
Tall fescue grass
This is an ideal grass for your clay soil lawn. As a cool-season grass, you should avoid planting it in places that experience hot weather. It has a coarse texture, but some varieties have finer blades that include the dwarf turf-type and turf-type fescue.
The tall fescue grass has roots that can penetrate deep into the ground and can do better in clay soil with a high organic matter content.
It will grow well if planted in partial shade or full sun.
Some people love the Bermuda grass because of its striking and beautiful emerald green shade that you will find in golf courses and public parks. Bermuda grass can grow quite well in clay soil, but as a warm-weather grass, it will not fare well in cold areas. This type of grass can be used in high traffic areas and also in pasture areas. It will grow well in clay soils because of its root system that produces deep rhizomes and can grow vigorously if left unchecked.
It does well in very wet areas that get lots of sunlight, but may not be the best grass if you have a very shady area.
This is another grass you can grow in clay soil that is drought tolerant and can handle the low water conditions in clay soil and is perfect for low maintenance areas.
It requires minimal care and watering. This grass goes dormant in November-January then in March and April it starts becoming green.
It has a deep root system that makes it perfect for growing in clay soil and is better suited for urban and suburban lawns and can also be used as fodder in pasture areas.
This grass will also do well in clay soil and a cooler environment.
It’s good for high traffic areas like golf courses and playgrounds, your front lawn, or in a pasture.
This grass prefers sunny areas and will not do well in places with lots of shade.
Clay soil may be hard to work with if you’re trying to plant grass, but if you take steps to improve and maintain it, you’ll enjoy the benefits clay has to offer and get healthy soil and grass.
What is the best fertilizer for clay soil?
If you’re gardening in clay soil, you can use granulated fertilizer, organic fertilizer, liquid fertilizer, and slow-release fertilizer.
Can you add too much gypsum to the soil?
Most farmers use gypsum to salvage alkaline soils, but applying too much into the soil can eliminate essential nutrients from the soil like iron, aluminum, and manganese which can lead to poor plant growth.