Gardening Tips

Your Guide To Different Soil Types

Anna Sharples 21st April 2020

If you are keen to start or grow your garden, you have many different decisions to make. What vegetables and fruits do you want to grow, what types of flowers will look best in your space, what designs do you want to implement, and what kind of garden furniture will you choose.

That said, before you start scrolling through the diverse range of wood benches available online, you need to make a much more basic choice – what type of soil should you use? Not only will this decision depend on the soil you already have in your garden, it will also vary based on what you are planning to grow.

We’ve compiled a comprehensive guide to help you understand the six main different soil types so that you can get started in the garden as soon as possible.

What is soil?

Soil is a broad term that is used in different ways by different people. Most people define soil as the unconsolidated loose material (not including rock) that covers the Earth’s outer mantle. This includes lake clay, silty deposits, sand dunes, estuary mud, and boulder clay, just to name a few different terrains.

However, for most gardeners and farmers, the term soil is used to refer to the top 40 cm of the ground into which you plant seeds and harvest vegetables from. However, from a scientific perspective, soil usually refers to the 1.5 – 2 metres beneath the surface.[i]

For the purpose of your garden, you are probably most interested in the topsoil. This is the crumbly material closest to the surface that leaves your fingers looking ‘dirty.’ It is typically comprised of mineral particles, sand, clay, small stones, and the organic materials left from decomposed plants. Its dark colour is caused by the humus layer, which is organic matter that reacts with the fluids on your skin and stains your hands with ‘dirt.’ Mixed in with the soil you will also find a lattice of roots and many small insects.

What are the different types of soils?

There are six main types of soil that you will find in your garden.

Clay soil

Clay soil is sometimes also called ‘heavy soil,’ and it is abundant in fine clay particles, typically more than 30% of its volume. While they can be sticky and hard to manage, this is fertile soil that is prized for growing vegetables and grains. The clays within the soil shrink and swell as they get dry and wet, and can be easily damaged and compacted when walked upon and dug into. While clay soil tends to take longer to warm up in the spring and summer months, it can handle drought in a more robust way that other soil types.

Sandy soil

This type of soil is light, dry, and warm. It tends to more acidic than other types, and has fewer nutrients. If you are wondering how to make soil more acidic, you can do this by adding some sandy soil into your mix. Sandy soil is also perfect for gardens that need quick water drainage, and they warm up very quickly in the spring and summer.

If you want to boost its nutrient count, you can add organic matter or compost, which will also improve its hydration capacity.

Silt soils

Silty soils contain up to 80% silt, and include sandy silt loam and silt loam. They are known for their silky textures, and were formed millennia ago from river, glacial, marine and wind-blown deposits. They require some form of drainage, and are very fertile owing to their high available water capacity.

Loam soil

Loam soil is often considered the ideal soil for growing all manner of soil. Loam is usually comprised of an equal mixture of silt, sand, and clay, giving it the benefits of each without the associated disadvantages.[ii]

Peat soils

Peat soils are rich in organic material, formed of decomposed plant materials compressed for millennia in watery anaerobic conditions. Peat is found in bogs (also called peatland and mires), which cover approximately 3% of the world’s surface, found in both the temperate and tropical regions of South East Asia, South America, the Caribbean, North America, and Europe.[iii]

In anaerobic conditions, the decomposition process of micro organisms is considerably slowed, which results in the accumulation of high carbon levels. Its ability to absorb carbon is one of the reasons that bogs are considered so important in the fight against climate change.

Lime rich / chalky soils

Alkaline soils that are rich is lime and chalk are found all over Britain, and are often referred to as chalky. While they are commonly used in the British agriculture industry, they can be quite challenging to the home gardener. They are often stony and shallow, and cause added compost and organic materials to decompose rapidly, which makes it hard to keep it fertile. If you have chalky soils, you should choose plants that are known to thrive in these alkaline conditions.[iv]

How to find out what type of soil you have in your garden?
In order to assess the type of soil you have in your garden, you will need to feel it and look at it closely, and you may need to add water to it and rolling it in your hands. Even if you have a small plot, you might still have a number of different types of soil in your garden. Try to create your main beds in the areas in which you have the best soil, and do your hard landscaping in the areas with poor soil quality.[v]

Here are some tips and tricks to identifying the soil in your garden.

Clay soil feels lumpy, sticky, and slimy when you wet it and ball it in your hands. It will roll easily into a ball.
Sandy soil will roll into a crumbly ball, but will fall apart easily.
Silty soil is smooth and will roll easily into a ball, but won’t hold its shape as well as a clay soil ball.
Loam will easily roll into a ball, but will not hold its shape as easily as clay or silt soil, and will feel the most like ‘dirt.’
Peat soil is rare in gardens. It’s very dark, and feels spongy when you squeeze it.
Chalky soil can be quite stony, and is very hard to roll into a ball. You will likely see small pieces of chalk and stone visible.

Soil care tips for all soil types

No matter what type you have in your garden, here are some ways that you can make the most of your soil.[vi]

Look into what type of soil your plants prefer – Most plants favour neutral soil, but there are some types out there that prefer acidic or alkaline soil. Do some research into your preferred plants to ensure that you have the right soil to accommodate what they need.
Make your soil more acidic – If you need to make your soil more acidic, add aluminium sulfate or sulphur.
Make your soil more alkaline – If you need to make the soil more alkaline, add ground lime.
Adding more nutrients – If you need to add more nutrients to your soil and improve its texture, add compost, manure, or other organic matter.
Aerate clay soil – Clay soil is rich and heavy, and it can often benefit from aeration and the addition of rotted organic material to improve its soil structure.
Add bulky organic matter to chalky soil – This will add minerals and nutrients to this notoriously difficult soil.
Feed your soil like you feed your plants – Treat your soil like you treat your plants, and make sure it has enough Nitrogen, Phosphorus and Potassium by adding fertilisers.
Renew your soil with ‘green manure’ crops – After harvesting a crop, renew the nutrients in the soil by planting green manure crops, such as legumes, clover, and buckwheat, all of which add nitrogen to the soil and adding aeration, drainage, and texture.
Add living organisms when possible – Adding worms, the mycorrhize fungus, and other beneficial insects will all help speed up composting and spread the nutrients throughout the soil.

While identifying your soil might seem complicated at first, it really does pay off to know what kind of soil you are dealing with. This will help you have a fantastic garden with abundant, fertile crops now, and for years to come.

Reference List

“1. What Is Soil?” 1. What Is Soil? | British Society of Soil Science, www.soils.org.uk/1-what-soil.

BBC Gardeners. “Find out Your Soil Type.” BBC Gardeners’ World Magazine, 27 May 2019, www.gardenersworld.com/plants/find-out-your-soil-type/.

“Clay Soils.” Clay Soils / RHS Gardening, www.rhs.org.uk/advice/profile?pid=620.

Contributors, HowStuffWorks.com. “What Is Loam Soil?” HowStuffWorks, HowStuffWorks, 9 Mar. 2011, home.howstuffworks.com/what-is-loam-soil.htm.

Cowan, Shannon. “Know Your Garden Soil: How to Make the Most of Your Soil Type.” Eartheasy Guides & Articles, learn.eartheasy.com/articles/know-your-garden-soil-how-to-make-the-most-of-your-soil-type/.

Efretuei, Arit. “Peat Soils.” The Permaculture Research Institute, 16 Oct. 2016, www.permaculturenews.org/2016/10/17/peat-soils/.

“Silty Soils.” Silty Soils – an Overview | ScienceDirect Topics, www.sciencedirect.com/topics/agricultural-and-biological-sciences/silty-soils.

“Soil Types.” Boughton, www.boughton.co.uk/products/topsoils/soil-types/.

[i] http://en.wikipedia.org/wiki/Soil

[ii] https://home.howstuffworks.com/what-is-loam-soil.htm

[iii] www.permaculturenews.org/2016/10/17/peat-soils/

[iv] https://www.rhs.org.uk/advice/profile?pid=762

[v] https://www.gardenersworld.com/plants/find-out-your-soil-type/\\\

[vi] https://learn.eartheasy.com/articles/know-your-garden-soil-how-to-make-the-most-of-your-soil-type/