What Is Topsoil? - Top Online Generals

Topsoil: Have you ever been on a riverbank and noticed layers of soil? You might have observed that the top layer was dark-colored and lush. This is topsoil, often referred to as the A or O horizon in soil. Take a closer look at the image on the screen. Notice the dark layer of topsoil where the plants root themselves.

Topsoil is defined as the top two to seven inches of soil that has the greatest organic matter content and microorganisms. Organic matter is what is left after plant roots, stems and leaves decompose. Topsoil is made up of carbon and nitrogen, microbes, and larger creatures such as worms, beetles, and other insects. Fertile topsoil also has concentrations of nutrients including potassium, phosphorus, and iron. Topsoil varies depending on geographic region and climate, as well as human activity.

Often, the blacker the topsoil is, the richer it is in nutrients, and the stronger its earthy smell. Rich, nutritive topsoil is able to hold onto more water. Consequently, greater nutrients and water availability allow topsoil to be more productive in terms of plant growth. The farmer tries to manage topsoil to allow for a reduction in the dependence on chemical fertilizers and additives to prevent disease.

What is topsoil used for?

Topsoil can be used to cover the ground, create new beds, and borders, or provide a base for turf laying or sowing grass seed. In paved gardens where there is no access to soil, topsoil can be used in raised beds for growing many plants, including vegetables.

What is good topsoil?

Good topsoil should be nutrient and mineral-rich and promote the growth of plants in your lawn or garden. Topsoil is the layer on top of the subsoil, and it sometimes differs because it has a high amount of organic matter, is nutrient-rich, and has low salts.

How is topsoil formed?

Topsoil formation is an incredibly slow process, typically taking 100 years for every inch of soil. It is formed from the weathering of rocks and the subsequent addition of organic material from decaying plants and animals. This enriches the soil and adds the nutrients essential to support plant life.

Topsoil Delivery

Topsoil is the upper layer of native soil. The highest concentration of microorganisms and organic matter can be found in these top two to eight inches of soil; however, the amount of organic matter varies in different soil types.

Most of the earth’s biological soil activity can be found in this layer. Topsoil is also the layer in which plants generally concentrate their roots.

There are four different elements that make up the composition of the soil. These elements are water, air, mineral particles, and organic matter. The amount of these elements can vary, which is why many gardeners check the soil conditions before planting. These conditions are important because topsoil is the layer where plants absorb their most important nutrients.

It should also be noted that topsoil differs from gardening soil and quality soil that is sold under the same name. Many forms of soil that are sold for gardening contain a mixture of many different mediums and soil types. For example, potting and gardening soil can contain organic matter, bark, and husks but not contain any actual soil. In addition, topsoil is used differently than most potting or garden soils. For example, topsoil is not often used for potted plants but is used for large-scale landscaping.

Home Depot Topsoil

The main nutrients found in topsoil are nitrogen, phosphorous, potassium, and magnesium. Each one has an important role to play in the soil’s fertility. Nitrogen is used for growth and promotes healthy stems and leaves. Potassium and magnesium help the plants to photosynthesize and create lush green leaves. Phosphorous is used to create the plant’s cells and DNA. All of these nutrients are naturally found in topsoil but in varying quantities and quality. They can be added to enrich the soil and increase fertility, whilst also improving the soil’s structure.

Varies Across Regions

Soil composition and structure vary considerably from area to area and it is constantly under the influence of its environment. People talk about having either clay or sandy soils in their gardens. Clay soils are harder to work with as they tend to harden and the nutrients are locked up in the sticky soil, although they do hold water a lot better. Sandy, loam soil, however, is the most ideal soil and is most often used in garden projects.

This soil is dark rich in color, lightweight and friable. As a quick test, it should be hard to roll up into a ball, and then quick to break up. Online Soil is located in the North West, where this type of soil dominates and produces incredibly fertile ground. We are lucky to be based in the North West and that we are able to share this soil with the rest of the country.

Acidic or Alkaline?

Good quality topsoil should have a pH value of between 5.5 and 7.5, in other words mildly acidic to slightly alkaline. This ensures the plants are able to take up the nutrients in the ground. Although most plants are able to cope with quite a range of pH values, if the ground is either too acidic or too alkaline then there will be problems. Although there are certain plants that prefer soil that is more extreme, such as the acid-loving rhododendrons and azaleas. Don’t forget that the pH is not the only important element of good topsoil though, it also needs an open structure to make sure there are good aeration and drainage, which stops nutrient lock-up.

Organic Topsoil

Some suppliers talk extensively about organic topsoil, but this is generally misleading. True organic topsoil would need to be taken from an organic-certified field, which would be prohibitively expensive. Therefore, a better decision would be to screen soil that has been improved by blending in organic composts to give it a higher organic content. The process of screening topsoil involves working the soil over a large mesh or screen to sieve stones and lumps out of the soil, a process that also acts to aerate the soil. Screen sizes should be 10mm or less for high-quality soils and up to 25mm for infill.

Pacific Topsoil

Topsoil refers to the top layer of soil that is high in organic matter and nutrients, formed by the slow weathering of rocks and decaying organic matter over thousands of years. It is typically used for making raised beds, new beds, borders, and bases for new lawns where the natural in situ soil is of poor quality or is not available, such as a courtyard.

Unfortunately, many gardens have poor-quality soil resulting from the soil becoming contaminated or stripped away during construction processes, especially prevalent in new builds. This means that it is often necessary to utilize quality topsoils to balance out the nutrient content for a project.

Topsoil typically comes available in three grades: economy, general-purpose, and premium, based on the amount of organic matter and nutrients within the soil. Topsoil is widely available to purchase in small and bulk bags for varied projects. All good quality topsoil including Boughton’s range of certified topsoils should meet British Standards 3882:2007.