How Topsoil is Made

One of the most common questions we get from novice gardeners is ‘What is topsoil?’ In this blog we will answer this question and discuss how different parts of soil differ.

What is Topsoil?

Soil is made up of several different layers known as ‘horizons’, each of these have their own unique characteristics and composition. The layers of colour can typically be seen on some riverbanks across the UK that have a deep cross section of the earth.

The layers of topsoil are as follows:

Humus (O horizon)

This is the very top layer of soil which is approximately 2 inches deep from the surface. This layer is mostly comprises of organic matter such as plants, grass, leaves etc.

Topsoil (A Horizon)

This is where most of the organic matter that are beneficial to your plants resides and is exactly what we mean when referring to topsoil. Topsoil is dark brown / black in colour and porous so it can hold lots of moisture and air, ideal for germinate your seeds. This layer is also where many insects, fungus and bacteria will live.

Subsoil (B Horizon)

Subsoil is deeper, mineral rich, and more compact than topsoil meaning only large deep roots will grow here. B Horizon is also noticeably lighter in colour.

Parent Material (C Horizon)

Parent material gets it’s name as the layers above it are developed from here very slowly over time, consisting of mostly large, solid rocks. It can take up to 500 years to produce 1 inch of soil.

Bedrock (R Horizon)

The very bottom of the soil is known as the bedrock, as it consists of huge various rocks such as granite, sandstone & basalt.

Screening Process:

The various levels of topsoil can be full of things you wouldn’t want to see in your garden such as large stones. To ensure we can provide a quality product, all of our topsoil is screened to 10mm. A screener is like a large industrial sieve which all of our topsoil passes through during the process.

Why Should I buy Topsoil?

When it comes to gardening, the importance of quality topsoil for your plants can’t be understated. Plants germinate and develop their roots in the topsoil layer, absorbing the essential nutrients they can.

Soils erode over-time

The quality of your soil will degrade as your plants and vegetables absorb it’s nutrients, this can make it more difficult to grow things in your soil over time. Although a smaller problem in your garden, when scaled up to industrial farming it can cause severe problems, particularly in poorer countries.

Soil pollution is also a concern as toxic chemicals from landfill sites have been found in the soil in some areas of the globe. This can pose a risk to human and plant life.

You can combat soil erosion by

  • Rotating your crops every season, leaving one area clear so it can recover.
  • Aerating your lawn to allow water and moisture to penetrate deeper into the soil
  • Maintaining a compost heap which you can add to your plants whenever needed
  • Recycle more and reduce your plastic waste.
Levelling areas:

Many gardens suffer from uneven land, and so laying topsoil is an ideal way of raising the soil level of your garden. You can even use topsoil to create a raised flower bed. Just be aware adding a thick layer of topsoil to grass will kill it.

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