A good gardener will know exactly what soil they have in their garden and pots, and which plants like the different types – because if they don’t, they risk disaster at worst or poor growth at best.
It’s important to know the different soil types and what you can grow in them, because your soil provides food, water, aeration and structure to your plants.
Those soils may look similar, they might even sometimes feel similar, but their characteristics can vary enormously, based on the size and texture of the particles and the chemical composition. There is more information on this at agrarianorganics.com/
The smallest elements are found in clay soil; at least a quarter of the composition will be built up of particles less than 0.002mm in size, which can be both a bonus and a hindrance.Anyone who has ever owned a clay pot will know how compacted and cracked the material can become. As the Royal Horticultural Society says: “Clay soils are easily compacted when trodden on while wet and they bake hard in summer, often cracking noticeably. These soils often test the gardener to the limits, but when managed properly with cultivation can be very rewarding to work with.”
Treat your soil by working in some organic matter before planting, and then go for it – trees such as Japanese Maple, crab apple and magnolia; shrubs including hydrangea, roses and lilac; and perennials like foxglove, bluebells, and peonies, can all thrive in clay. The next type of soil to consider is silt, which comprises particles up to 0.05mm and is very similar to clay soil in that it can be fertile, but again can be compacted easily into ruin.
The other extreme is sandy soil, which feels…sandy. Light and loose, it’s easy to identify with its coarse, gritty nature, and easy to work.But because the particles are bigger, rain and water can soon slip through the gaps and drain away what little nutrients are contained within, so again it is worth treatment with organic material to compensate.
Lavender and buddleia shrubs will benefit from sandy soil, as will various herbs such as rosemary and thyme, and wallflowers.The other element of your soil to consider is its pH value, which signifies whether the soil is acidic or alkali, or somewhere in-between. Plants which like high acidic qualities will not like alkaline, and vice versa.
Sandy soils are often acidic, while ‘chalky’ soils which often contain white lumps of visible stone are alkaline. Clay, perhaps unfortunately, can be either.
Kits exist to test the pH values of soil, but a quick way of telling is to take soil mixed with a little water into a muddy consistency, and pour vinegar over the top. If the mixture fizzes, it’s alkaline. Alternatively add a little baking soda, as if that fizzes the soil is acidic.
There is little point in trying to change the acidic make-up of your soil, so stick with the type, and if necessary grow your plants in large containers using compost.
Your soil may be a mix of several quantities and qualities of the different types such as in loam, a blend of clay, silt and sand which is regarded as a ‘gardener’s best friend’. But remember the consistencies and percentages of the various soils may change across just a few feet.
So touch and appearance may help you identify your material – but experience will help your success rate as well.