What Is Topsoil? The Pros & Cons of Each Type

Growing and maintaining an attractive lawn is directly related to having healthy, good-quality topsoil.

Also referred to as surface soil, this is where you will find most of your grass’ roots. The top layer of soil is vital to plant health as it has the greatest concentration of beneficial microorganisms, nutrients, and organic matter.

Topsoil is generally categorized as the outermost layer of soil that is typically five to ten inches deep. It is essential to understand the type of topsoil you currently have to better maintain or amend this important layer your lawn needs to grow full and healthy.

Here is what you should know about the different types of soil just beneath the surface.

Most Common Types of Topsoil

Topsoil is classified under a wide range of categories. Each of which that have their own unique benefits and disadvantages to work with.

The type of soil on your property often depends on your geographical region. If you are planning on taking lawn care seriously, you will learn that each type of soil needs to be maintained appropriately to be successful.

Clay Soil

Homeowners who battle clay soils understand that it can be difficult to work with at best!

You’ll find that clay ranges in color from grey to bright red. Sticky to the touch when wet, and heavy and hard to turn when dry, clay soil is often misunderstood and can be utilized to grow a good looking lawn.

Because of its stingy holding properties, clay soils are rich in nutrients! For this reason, clay can be quite fertile when cared for properly. The key is to amend clay soils with organic material to help open up space for air and water to move through and for roots to grow.

However, drainage can be a major issue with this soil-type. During times of high rainfall, poor drainage makes it hard for the root systems to get enough air. While in times of drought, clay can become hydrophobic, making it difficult to get water to the root zone.

Adding sand, quality topsoil, and peat moss to clay soils will drastically change its sticky nature over time and will yield better results. Applying biostimulants such as amino, humic, and fulvic acids will also enhance the richness of clay soils, unlocking their nutrients to be better used by your grass’ roots.

Sandy Soil

With clearly defined physical characteristics, lawns with sandy soil are almost instantly recognisable.

Sandy soils are dry and gritty to the touch. If you tried to roll slightly wet sandy soil in your palms, it would crumble through your fingers easily. This is because the particles in sandy soils have huge spaces between them.

Soils with high levels of sand simply cannot hold on to water – and as a result have trouble holding on to nutrients as well. The rapid drainage pushes the water and other essential nutrients straight through to places where the roots cannot reach. This means that lawns grown in sand will require more water and fertilizing than other soils.

The upside to sandy soil is that it’s relatively easy to move and warms up quickly in the spring. Anyone who has worked with sandy soil knows that it is very light and not difficult to cultivate.

Top-dressing with quality topsoil and peat moss in the spring and fall will enrich your sandy soil and help it to hold on to water and nutrients better over time.

Silt Soil

Silt soil can be a great soil for growing a healthy, lush lawn if drainage is provided and moisture is managed. Homeowners lucky enough to have this soil-type have some fertile ground to work with.

Silt soils are similar to sandy soils when dry except that their particle sizes are much smaller resulting in a feel that is soft to the touch. When you roll silt between your fingers, dirt is left on your skin with a smooth texture, kind of like flour. As a result of the smaller particle size, silt soil holds and utilizes water much better than sandy soils.

Due to the soft nature of silt it is easy to work with, but can become compacted quite quickly when wet leading to drainage issues. Although, overly wet silt isn’t the only issue as letting silt soils dry out can lead to other problems. Since their particle sizes are so small, dried out silt can easily be eroded by water and wind.

All this being said, silt soil still holds nutrients very well and the slow drainage of water makes them beneficial for growing grass. Periodically mixing in composted organic matter is usually needed to improve your soil’s drainage and structure.

Chalk Soil

Chalky soil is notorious for being difficult to work with. The challenges of having this soil-type can be quite overwhelming for a homeowner trying to grow the ideal lawn.

Generally rockier compared to other soil-types, chalk soils are named so because they often have a layer of chalk or limestone bedrock beneath the surface. This makes the soil quite difficult to work with as many grasses struggle to grow in such conditions.

Rocky soils like chalk have large amounts of space beneath the surface and are prone to drying out and losing water and nutrients in large quantities. Those who have chalky soils must be prepared to water and fertilize more frequently due to this characteristic.

Chalk soils are also very alkaline in nature, which sometimes leads to stunted root growth and yellowish leaves, called chlorosis. The high pH level is caused by the lime content in the soil profile and must be regularly amended to neutralize pH and improve water absorption.

If you have this soil-type at home you may think you are already destined for failure. Keep in mind, that having a great lawn in chalky soil can be done, but only with a lot of effort. Top-dressing periodically with quality topsoil, manure, and compost will build up nutrients and help with absorption over time.

Peat Soil

Peat soil, classified scientifically as a histosol, is formed from decomposed plants and animals in wet climates making this soil-type high in organic material.

Normally dark brown or black in color, peat soil is soft, easily compressed due to its high water content, and rich in organic matter. When wet peat soil is rolled, you won’t be able to form a ball easily. You’ll find that it’s spongy to the touch and when squeezed, water could be forced out.

This soil-type is acidic in nature, which tends to slow down the decomposition of organic materials, and leads to the soil having fewer nutrients. This means it needs to be kept well fed with fertilizer to help grass and plants get the essential food they need to grow strong and healthy.

Peat soil will heat up quickly during spring and can retain a lot of water through the wet season. Since it holds water so well, the soil may require amending to prevent waterlogging and to open up more space for air and nutrients to pass through.

Applying soil conditioners, such as lime or humic acid, will help your plants get the nutrients they need and improve the structure of peat soil for better root growth and nutrient uptake.

Loam Soil

Loam soil is widely regarded as the healthiest soil to grow plants in. It has a rich, dark brown appearance that feels moist and can often be clumped into a crumbly ball.

It contains a balanced blend of other soils with the standard mix being about 20% clay, 40% silt, and 40% sand. This combination of soils creates a mixture that all but eliminates the negative issues of each individual soil type.

For example, while clay soil tends to struggle with poor drainage and sandy soil tends to drain too quickly, loam soil provides a good middle ground. The balance of particles allows for optimal drainage and better nutrient uptake.

Even though loamy soils are ideal for growing flowers, garden vegetables, or turfgrass, all soils need to be well taken care of in order to maintain or improve soil health.

Most lawns will struggle with soil imbalances. Creating optimal loam is a lengthy and ongoing process. Amending your soil annually with organic matter such as garden compost, peat moss, composted manure, or high-quality topsoil will help push the needle in the right direction.