Soil Types Explained: What soil type do I have?
Lee Burkhill: Award Winning Designer & BBC 1's Garden Rescue Presenters Official Blog
The soil type that you have in your garden can make or break your plans for a successful garden design. Your plants will only be as successful as the preparation and planning that you, the gardener, put in! Rather than thinking of soil as dirt, you need to start treating it as the life force of your garden. Where all microbes, bacteria, and microorganisms live, allowing your plants to grow successfully.
The last thing you want to do is to spend hundreds of pounds on your garden to find all your plants wilting or dying. Establishing the type of soil is paramount in making sure that you're selecting the right plants, fertiliser and conditions for growth.
Let's take a look at the types of soil you may be dealing with and how best to work with them during your gardening.
The perfect Loam a mix of inert and organic matter, open, moisture retentive and easy to work with!
Understanding why soil is such an important part of your garden is essential. Often soil is confused with dirt or garden compost. However, the soil is neither of these. Soil is its own organic living organism. Whereas dirt is inert material and compost is organic matter that is breaking down. Let's have a closer look at the key soil terms below.
Bits of inert debris, grit, rock and sand with no organic ie living matter.
Soil is a complex mix of particles, minerals, living organisms, dead organic matter and bedrock (ground-down stone). It creates a rich living tapestry perfect for plants and wildlife to thrive in. It's the building block of all successful gardening and garden design.
Loam is the 'near perfect' healthy mix of clay, silt and sandy particles found in soil. Think of it as the ideal mix of balance, but rarely achieved! 40% Sand, 40% Silt and 20% Clay. It’s a subterm for soil.
Compost is organic matter that has been broken down naturally in a recycling cycle. It means its high in nutrients, holds onto moisture and contains a light airy texture. You can make your own compost at home to help boost your soil health.
The soil is composed of both organic (dead & living) and inorganic (mineral) elements. It's created over time and is present in layers known as soil horizons, which, if you dig down, you can see. It is composed of tiny fragments of stone which have been weathered either by the elements or by organisms such as lichen eating away at stone surfaces. These tiny fragments are then built up over time in layers mixed with organic material, creating layers of soil.
The organic matter usually comes from trees dropping leaves, plants dying back each year, and animals grazing and dropping their own natural manure. It is an ever-evolving situation of things growing and then decomposing that creates soil.
Soil horizons start with the very top organic layer, moving onto topsoil, which most people are familiar with. The next layer is subsoil, and lastly, the parent material consists of solid rocks, sand, and gravel. Don't worry; the science lesson will soon be over, but it is important to understand this to know why knowing your soil type is important.
A gardener is concerned with making sure that the structure of the soil is open, free-draining contains organic matter (for both nutrients and moisture retention) and is easy to work with. This is a fine balance, and over-cultivation, i.e. digging the soil too frequently can do more harm than good! This is why a number of gardeners, myself included, are choosing to follow 'No dig' gardening principles.
This refers to the amount of Sand, Silt and Clay present in a soil sample.
Most people will have heard of sandy, silty, or clay soil types. They may have referred to their own soil as heavy clay or very sandy. These are the mineral fractions of the soil and contain no organic matter.
In reality, the soil is a mixture of these elements along with organic matter and mineral elements all of which dictate how the nutrient or organic elements are contained or lost. The soil type will determine how easily they hold onto water and nutrients. This is why it's important to know what soil type you are working with!
This soil is a mix of 30% Sand, 40% Silt, and 30% Clay, nearly perfect!
Loam is the technical term for perfect soil. Whilst there are subclassifications such as sandy loam, clay loam, and silt loam, this general term is used for free-draining soil, which is a 'perfect' blend of the three main components. Very roughly, so the horticulturists don't kill me, loam is
Your soil type will be a mix of Sand, Silt, or Clay. However, the weighting of each element requires a much closer inspection and test. The classifications below are not exact but give you the benefits for each soil type. I always advise that a garden survey is the best way of working out the soil types and pH I offer in all my Garden Design services. Establishing what soil you have will, in turn, lead to your plant selection.
Sandy soil is gritty and free draining like the above image.
Clay soil is fantastically high in nutrients but a pain to work with as it's so thick and sticky.
Silty soil is very fine and contains more nutrients than sand, but it suffers from compaction issues when walked on.
The above should help you in assessing roughly what soil type you have but ideally, you need an expert as it isn't just the soil type but also the aspect, PH and other environmental factors that will affect the success of your garden design. By taking a handful of soil and squeezing it when slightly wet, you can usually get a good idea of whether it is:
Sandy soil will drain really quickly, so this can be an indicator. If you dig a hole one spade depths deep and then pour in a watering can of water, then sandy soil should drain within an hour, whereas clay won't.
Always choose plants that suit the soil you have. That way you will get the very best out of your garden.
Soil that is silty is in the minority and is usually found near river beds or old water courses. Most soils in the UK are either sandy or clay-based.
It matters because if you, for example, have heavy clay soil you are going to struggle to grow bulbs, annuals or lightly rooting plants as clay is dense and difficult to work with. They will simply rot, given their high water retention. You will need to work in a considerable amount of organic matter to such soils to help aid aeration and drainage.
You will, however, be able to grow moisture-loving plants such as Iris pseudacorus in clay soil. So you can see how the right plant for the right place comes into play. You're not going to be able to completely change the soil type, only tweak it. It is best to work with what you have got. You will need to assess the
You will need to assess the planting scheme you want for the soil type you have. It's not impossible to completely change your soil type. It is highly improbable, given the fact you would have to remove it all with a digger to replace it fully!
The only way to work with it is via organic dressings and some very specific planting plans that cater to your soil type. Finding plants that will tolerate or even thrive in your soil type can save you much heartache and ensure you spend more time enjoying your garden rather than grieving over plants! With my design services, Garden Ninja can help assess soil types and provide suitable planning schemes for this.
So we've talked about the fantastic life force of soil and how soil provides the very elements that your plants need to survive: stability, food and water. However, when the soil has been over-cultivated or walked on repeatedly, it can become compacted like a concrete road of firm grit. It often goes a grey colour as the top layer develops a soil cap. A soil cap is a hard crust that prevents water and organic matter from entering or leaving the soil. It's a prison for the soil organisms.
Digging in organic matter breaks up soil, aids moisture retention and adds oxygen, as shown in the image above.
If you have compacted soil, the advice is to cultivate it and add organic matter such as compost or lawn clippings. By adding a small amount of this, it helps keep the air spaces relatively free in the soil. The party starts again with all those microorganisms, and you're ready to plant for success!
Once cultivated your soil should look healthier, darker in colour and much lighter to work with. Be careful not to then start walking repeatedly over it and compacting it again. If you need to walk that route, consider a path or using boards to walk on to protect the soil.
Again, soil pH is incredibly important, as this will show whether your soil is acidic, neutral, or alkaline. Plants do have a preference for the pH of the soil, so accurately assessing what the pH is can save you time and money with plant choices. There's no point expecting an Azalea to grow in an alkaline soil bed when it is ericaceous or acid-loving; likewise, there is no point trying to force alkaline-loving plants into acidic soil.
Most UK soils are between 5.5 and 7.5. The lower register is more acidic, and the higher the alkaline content of the soil type. However, you may find that different parts of your garden have different PHs. So it is worthwhile to check your garden in different places and record the results.
It must be stressed that most plants are perfectly happy in this 5.5-7.5 position, with a few exceptions.
Some plants prefer acidic or ericaceous soil below 5.5. These are usually plants from moors, dry heaths, and peat bogs where acidic conditions are present. They have adapted to take up nutrients available in acidic conditions, e.g., Erica carnea (Winter Heather).
Other plants are adapted to more ‘chalky’ soils where alkalinity is high. eg - Convallaria majalis (Lily of the Valley).
Alternatively, you can buy over-the-counter soil testing kits. These vary from mixing soil with a solution using litmus paper to assess the PH or electronic probe PH testers. Ideally, you would need multiple checks around each border to ensure you have a proper view of your garden's soil type.
I use an electronic soil PH meter like the one above to measure soil PH.
Take your time, as each test can take around 10 minutes. Map out the PH readings on a plan of your garden site to ensure you know exactly what to plant where.
Understanding your soil type and how it is created is a really important part of becoming a successful gardener. Many gardeners ignore soil at their peril and have lacklustre planting results. By taking some time to get to know the soil and treating it as a precious resource, you will become a far better and more mindful gardener.
Understanding your soil type is crucial for effective gardening. It allows you to choose plants that thrive in your garden's soil conditions, ensuring better growth and health. Knowing your soil type also helps you manage watering needs, nutrient levels, pH balance, and soil health more effectively. By understanding the soil's properties, you can implement pest and disease management strategies and plan irrigation systems accordingly. Soil type also influences garden design decisions, such as plant placement and hardscaping choices. Overall, knowledge of soil type empowers gardeners to create and maintain healthier, more vibrant gardens.
If you have questions about your soil type why not Tweet, Facebook or Instagram me with your pictures? You can also follow me on YouTube where I’ve got plenty of garden guide vlogs.
JOIN THE NINJAS
Join our Ninja community for extra guides & Discount Codes for Online Garden Courses!
To my Newsletter
To my YouTube channel
I am moving to Churchtown soon, can I grow rhododendrons there?
Hi Jean.
You can grow them pretty much any where in the right conditions. Acidic soil and dappled shade are a must if you want them to put on a good show. However, I’ve grown them in full sun but you do need to mulch them each year. Pruning is only light touch and they give a good show all year round. Let me know what cultivars you choose and how you get on. Lee
Very informative guide, clay soil can be quite annoying down south!