When you are planning a garden, identifying your soil type is a crucial early step. Without knowing what type of soil you have, you may end up planting plants that will simply not survive.
In this post, we will look at the different soil types that exist, and how to identify which one you have and what you can grow in them.
DIFFERENT TYPES OF SOIL
Clay
Clay soils are very heavy soils. Because clay soils are made up of a high proportion of clay particles, they tend to ‘puddle’ when not worked properly. ‘Puddling’ is when the soil turns into a sticky mass and gets very hard and cracks when it dries out. In this condition, the soil does not allow good drainage at all and plant roots will struggle to penetrate it.
Clay soil is difficult to work with as you have to know just the right time to work with it to avoid ‘puddling’. The soil must be dug at just the right humidity. Clay soil can be improved by adding manure or compost.
Sand
Sandy soils are light soils. They contain a high proportion of sand making them gritty and not sticky like clay soils. Sandy soil drains very quickly and is prone to drying out. The soil is not very nutritious so to grow successfully on it, you need to keep incorporating lots of organic matter such as compost or manure. The nutrients in this will wash away by the rain very quickly hence you have to keep adding more.
Silt
Silt soil is made up of intermediate particles that are larger than clay but finer than sand. It feels fine and almost floury and dust like when dry. When wet, silt is slippery, not grainy or rocky. Silt is fertile and has good drainage and airflow but still can be improved by adding organic matter such as compost or manure.
Loam
Loam soil is a sort of halfway point between sandy, clay and silt soils. It incorporates both, sand and clay and is the perfect soil type for gardening. This soil is fertile, drains well while still retaining some moisture and is easy to work with. Often the soil isn’t a perfect mixture of clay, silt and sand but tends to be either a bit on the sandy or clay side. Any soil can be improved by adding organic matter and loam is no different. You should incorporate some at least annually.
Peat
Peat soils are formed from vegetable matter that has been compressed underwater instead of rotting away. When this water is drained off, you are left with peat soil. This type of soil is incredibly rare in gardens as it is essentially pure compost. It is very nutritious and does retain moisture well.
Chalk
Chalky soil has quite large grains and tends to be stony but it can be both, light and heavy. In very chalky soils, you may actually have visible bits of white chalky stones. This type of soil is very alkaline and cannot be successfully acidified. The soil is not very nutritious but it does drain well.
HOW TO IDENTIFY WHICH TYPE OF SOIL YOU HAVE
Clay
Wet a small patch of soil and pick a clump up with your bare hand. Squish it around in your hands – if it feels quite sticky, smooth and can easily be shaped into a ball or log with a smoothed out surface, this would indicate clay soil. Additionally, if it’s currently summer, take stock of how the soil looks. Does it have cracks running through it? If so, this is also indicative of clay soil.
You can also pour some water onto your soil and see how quickly it drains. If the water drains slowly, this is likely to be clay.
Sand
Sandy soil is gritty. If you squish it, you can feel the sand grains within. Unlike clay, if you are to wet it and try to make a smooth ball, you will fail. The soil will not stick together.
If you pour water on sandy soil, it should drain very quickly.
Silt
When wet, silt soil is not grainy like sandy soil but it is also not sticky like clay soil. If you grab a handful of relatively dry soil and squeeze it, the soil will hold its squeezed shape for a short time only. Pure silt soils are rare in gardens so if your soil has these characteristics, it’s more likely to be loam.
Loam
When you look at the soil, loam doesn’t look dusty like silt but has slightly more texture and feels almost slightly damp. If you squeeze it, it feels very similar to silt. It will not be grainy and it should hold the squeezed shape for a short time before falling apart. As pure silt soils are very rare, your soil is likely to be loam rather than pure silt if it feels like this.
Peat
Peat soil feels damp and spongy. If you squeeze it, it will feel like it’s springing back at you. This type of soil is incredibly rare in gardens so it’s not likely that this is your soil type.
Chalk
This soil will be gritty and will have many stones in it. Similar to sand, it does not stick together. If you put some soil into a container and fill it with water, after around 12 hours, the water will have coloured pale grey and the bottom of the container will have whitish grit particles.
WHAT TO GROW IN EACH SOIL TYPE
Clay
Clay soil takes longer to heat up and thus if you plan on growing vegetables, you are unlikely to be able to grow early crops in clay soil. Equally, any blooming flowers you plant will tend to bloom a bit later than in other soil types.
Naturally, clay soil tends to be nutritious and full of potash. It is frequently on the alkaline side but this is not always the case. It also retains moisture very well.
Vegetable-wise, if you incorporate plenty of manure or compost and learn how to tend to the soil without ‘puddling’ it, you should be able to grow potatoes, beans and cruciferous vegetables. Because of its alkalinity avoid acid loving edibles such as blueberries and raspberries.
In terms of decorative plants, you can grow many types such as flowers including roses, hydrangea and foxglove, as well as many trees such as elderberry, oak and apple. There really are many varieties that will grow well in clay so if this is your soil type – don’t despair!
Sand
Opposite to clay, sandy soil is early soil because it heats up very quickly in the spring. This means that early vegetables and blooming flowers are able to grow in it.
Because the soil is not very nutritious, it lacks potash and phosphates. You have to keep adding organic matter to make it more nutritious but this won’t last very long. The soil tends to be acidic.
Because the soil tends to dry out, the best plants to grow are deep rooted ones that can reach for the moisture from deep within. Edibles such as root vegetables, potatoes and Mediterranean herbs will do well in sandy soil, provided you are adding compost or manure. However, for root vegetables such as carrots and parsnips, do not add manure too close to planting time as it will make them fork.
For decorative plants, you need to pick ones that can survive drier conditions such as cosmos, hosta, lavender and crape myrtle. In terms of trees, there are many varieties but some of the most beautiful are cherry, magnolia and maple.
Silt
Silt has decent drainage while at the same retaining some moisture and is fertile. It is good soil for growing edibles and indeed if you have silt soil you should be able to grow pretty much any vegetable successfully. Equally, if you want to grow decorative plants, you have a huge range of options.
Loam
Loam is excellent soil because it has good drainage and moisture retention, it warms up quickly in the spring and yet doesn’t dry out quickly in the summer and it is nutritious. Similar to silt, you can grow pretty much anything successfully in loam.
Peat
If you are fortunate enough to live on a patch of well drained peat then you have an incredible opportunity to grow every type of vegetable you can think of – the soil is pure manure! If you’re not much of a food grower then you shouldn’t have any issues growing decorative plants. Of course remember to consider other plant requirements such as acidity, sun and wind exposure, temperature etc.
Chalk
Chalk is highly alkaline and so you should avoid growing acid loving plants such as blueberries, raspberries, camellias and rhododendrons.
You can grow some vegetables but make sure you incorporate plenty of organic matter. Try growing cruciferous vegetables, sweetcorn and roots – as this is a grainy soil, you want vegetables that have deep roots to grab moisture from within.
In terms of decorative plants, there are quite a lot of good choices. There are climbers such as clematis and passiflora; flowers such as echinacea, geranium, and helianthus; trees such as acer, cherry and apple or shrubs such as fuchsia, forsythia and hebe.
I know starting a garden can seem a little daunting but I hope that this guide will help you make sense of one of the things you need to consider. Have you got experience in growing plants in any of these soil types? If so we’d all love to hear about it below!
