What is Topsoil Used for? Is It Important?

For healthy gardens, flourishing flowers, blooming plants, and fresh vegetables, the powerhouse behind all this growing force is topsoil, a key component for plant growth that works close to the surface. Topsoil is the upper layer of soil 2-8 inches deep and high in organic matter and nutrients, necessary factors for the development of plants. As far as garden soil goes, it plays a crucial role.  

Are you wondering, “What is topsoil used for?” If you’re a budding gardener, knowing the importance of topsoil and its uses is essential. In this blog, we’ll uncover the use of topsoil and the reasons why it’s so vital for a healthy garden. 

What is Topsoil?

Are you wondering, “What is topsoil?” Before we dive into the importance of topsoil, understanding what it is is essential. Topsoil is the upper layer of soil, approximately 2-8 inches deep. It contains most of the ground’s fertility and nutrients, which is why it’s so significant in the growth of plants. It comprises a dynamic mix of organic materials, like sand, clay, silt, and broken-down organic matter, also known as humus. Humus is a highly decomposed organic matter made up of plant debris, twigs, and dead insects. The look of topsoil is generally dark and rich in color. Its texture is crumbly, and it has a natural, earthy smell. 

What is Topsoil Used for?

The blend of materials in topsoil creates the ideal conditions for living things to grow and thrive right under our feet. Topsoil is the layer above the subsoil that contributes to the overall stability and structure of your soil profile while providing nutrients and aiding with drainage. 

Subsoil and topsoil work together to create an effective system where plants can thrive. Topsoil provides the necessary nutrients for roots, and subsoil’s drainage properties ensure a balance between the air and water in the soil to prevent waterlogging. 

Topsoil is used for: 

• Plant growth 
• Soil improvement, like structure, aeration and drainage
• Landscaping projects
• Improving soil fertility 
• Soil restoration 

How is Topsoil Formed?

You might be surprised to know that soil formation is a slow process that takes a long time to become the valuable garden and farming essential it is today. It’s formed slowly by the weathering of rocks and decaying organic matter throughout thousands of years. Weathered rocks crumble due to the effects of temperature fluctuations, wind, and rain. They’re broken down into smaller pieces, setting the groundwork for topsoil formation. 

With every rock that crumbles, organic matter plays a significant role. Plant residue, leaves and other organic materials decompose with the help of microorganisms in the ground. This turns the complex organic compounds into richer nutrients, enhancing the growing qualities of the soil and making it far more fertile. This becomes topsoil and an enriched foundation layer that is ideal for optimum plant growth.

Is Topsoil Important?

Is topsoil important? The short answer is yes.  Topsoil is vitally important for the growth and health of plants, and it all comes down to one key reason: the nutrients it provides. Packed full of essential organic matter and due to the nutrients it offers, topsoil is critical to a flourishing garden. 

The nutrients found in the soil are nitrogen, phosphorus, potassium, and magnesium. Each one plays a vital role in a plant’s growth and development, making it an absolute must-have for gardeners worldwide.

Here are the essential nutrients and the critical role they play:

Nitrogen

Nitrogen is used for plant growth and promotes vibrant, lush greenery, ideal for a garden’s look and health. It is the powerhouse behind plant growth, promoting healthy stems and leaves.

Phosphorus

Phosphorus is another critical component of topsoil, promoting root and flower development. This element is used to create the plant cells’ DNA, which helps with energy transfer within a plant. This sets the foundations to enable plants to develop a robust root system. 

Potassium

Potassium plays a critical role in a plant’s resilience, as it helps with disease resistance, enzyme activation, and water uptake. This is ideal as it helps a plant stand firm against environmental stress factors. It also works to regulate the opening and closing of the tiny pores on the leaves (stomata), which helps reduce water loss and promotes gas exchange.

Magnesium

Magnesium is essential for the proper function of photosynthesis, helping plants capture and convert sunlight into energy. Magnesium also helps with energy transfer and stress tolerance in plants, helping them to remain sturdy against adverse conditions such as temperature fluctuations. 

These key ingredients are the life-giving essentials for plants and the reason why topsoil is vital for both gardening and farming success. While all of these ingredients are found in topsoil, it’s important to consider that they vary in quantities and sometimes in quality. However, they can be added to soil to improve its structure and fertility. 

The Global Importance of Topsoil

The essential role topsoil plays in our back gardens is replicated globally, with 95% of the world’s food grown in this top layer of soil. However, this kind of soil might not always be as accessible as it is today because it is susceptible to high levels of rainfall or flooding, both of which can wash away this vital source.

The lack of soil would have a detrimental impact on the growth of crops, too, so conservation practices like cover cropping and contour plowing are essential. 

The two practices are as follows: 

• Cover cropping is the process of planting crops to cover the soil, protecting it from soil erosion and encouraging soil fertility and quality. 
• Contour plowing is the farming practice of planting crops on a slope to create contours that decrease topsoil movement and help avoid soil erosion. 

Protecting the top layer of soil is essential as its absence could have an extreme impact on agricultural productivity. Not to mention the stable environment where the ecosystem can thrive.

What’s the Difference Between Topsoil and Garden Soil?

In the world of gardening, the terms topsoil and garden soil are often confused or used interchangeably. We’re here to set the record straight and let you know that there actually is a difference, and the two types of soil play different roles with their characteristics and purposes.

Topsoil’s Characteristics and Purposes

Topsoil is the top layer of soil that lies above the sublayer and is usually taken from fields or designated areas. It is then ‘screened’ whereby additional matter, such as small stones and debris, is removed before being sold for garden or landscaping purposes.   As we’ve previously mentioned, topsoil’s primary purpose is to provide essential nutrients and a stable environment for plants to grow and thrive. Typically, topsoil is between 2-12 inches in depth and contains the majority of the fertility of the soil, with its blend of organic matter, minerals, and microorganisms. 

Garden Soil’s Characteristics and Purposes

Garden soil is a unique blend of premixed soils that have been graded and cleaned of weeds and pests. It is usually ready bagged and sold in home improvement stores or garden centres. This kind of soil is usually a combination of topsoil, peat moss or peat substitute, compost, bark shedding, and fertilizer. Often, this mix is made to enhance the conditions of the soil and create an ideal environment for plant growth. It can also be made up in specific blends to suit specific types of plants such as ericaceous. In some cases, garden soils have added nutrients and organic matter added to enhance soil structure, improve soil drainage, and promote aeration.

When to Use Topsoil

If you want to embark on a larger landscaping project, like planting multiple trees and shrubs, or creating a garden from scratch, using a standard topsoil mixture is your best bet. Topsoil is great for filling in holes in any areas where you’re lacking soil to level the ground, or to infill raised flower beds. The nutrients and organic matter in the topsoil will work their way down into the subsoil underneath and provide an excellent foundation for your new planting schemes.  If you’re planning a large project, buying topsoil in bulk is most likely the most cost-effective option. 

When to Use Garden Soil

Adding garden soil to existing vegetable patches or flower gardens will quickly, within a growing season, restore the nutrients that plants from the previous season, have used up. Garden soil is already high in organic matter, meaning it’s full of nutrients and has excellent drainage properties.

In some cases, for example, if you’re building a raised garden, you can use both topsoil and garden soil together. Using topsoil as the underlayer to a depth that will allow for the development of plant roots to take a firm hold. Then apply a top layer 6-8 inches deep of garden soil for optimum growing conditions. 

How Much Topsoil Do I Need?

You might be wondering, “How much topsoil do I need?” Working out the amount of soil you need depends on several factors, like the depth and size of the area you plan to cover. Start by measuring in feet the area and work out the length and width you plan to cover. The easiest way is to measure in meters, as you can work out the volume in cubic meters. The calculation is as follows, volume = length x width x depth, and once you’ve worked it out, you’ll know how many bulk bags you’ll need. 

When purchasing soil, it’s always a good idea to round up, to ensure that you have enough to complete your garden project.

Final Thoughts

Having explored the key components of topsoil and the benefits it has on the strength, resilience, and health of plants, it’s clear that it’s an essential element of a garden. As you embark on your gardening ventures, don’t underestimate the importance of topsoil and the ways it can transform your garden into a vibrant, healthy, and flourishing environment. Now you no longer need to wonder, “What is topsoil used for?” 

Do you want to know more? Visit our blogs for more information about improving the health of your garden and discover tips and advice for creating your ideal outdoor space. 

Frequently Asked Questions

Here are some frequently asked questions about topsoil and its importance in gardening: