Soil is the essence of your garden. It’s packed with minerals and organisms, which are essential to nurture your plants and help them grow. Give your soil a helping hand by offering a range of affordable, high quality soil improvers. They’ll improve the texture and performance of the soil by increasing organic matter and moisture retention.

Think of your soil as an environment which needs to possess key features – the most important being the ability to enable water to drain into the sub layers below and allowing air to circulate around the plant root area. Soil needs as much pore space (holes) as the actual soil itself.

Soil should be made up of tiny particles all joined together by humus – this gives the soil that crumbly feel, making it easier to work with. The spaces between the particles provide the route for water and air movement as well as soil microbes, including worms, which are considered to be Mother Nature’s natural aerators.

The soil in your garden may possess a range of textures and these can include heavy clays or predominately sandy materials. Each of these soils can offer benefits and drawbacks to your gardening efforts.

In order to improve your soil, prior to planting out or seeding, ask yourself the following questions;

1. How deep should the topsoil layer be?

It needs to be 8 – 12 inches. This is an extremely important layer, as it must supply the nutrients, water and air to the plant’s root system. Larger plants with large roots require a deeper topsoil layer. The better aggregated the top soil layer, the greater a plant performs. The soil volume in this environment is enormous – to improve/change it, requires very large amounts of humus.

2 How well does it drain?

The best soils retain around 25% moisture to meet plants demands. Too much and the water forces out valuable soil air and increases the weight within the soil. This leads to compaction and as such a dense solid environment not suitable for optimum plant performance. Drainage is important, opening up clay type soils, and creating a route for the water to flow downwards is critical, however a balance must be created to ensure enough is retained. Sandy soils leach readily and transfer valuable soil nutrients downward. To ensure this is reversed, water must be rained within the large spaces between the sand particles.

3 How rich is it in plant nutrients?

Plants do not perform without plant food. Plants require a whole range of nutrients including, nitrogen (for greener leaves), phosphorus (stronger roots), potassium (better overall colour) etc.

Some of these nutrients will be supplied from the existing soil; however, to ensure the plants receive adequate quantities, it’s best to introduce additional amounts. The best way to improve the performance of the nutrients is to feed the soil which will in turn feed the plant. Adopting this programme ensures the plants receive the benefits of the nutrients over an extended period of time, without the need for continual applications i.e. humus rich soil improvers provide a supply of slow release nutrients.

 What to do next?

One of the best ways to improve heavy clay or sandy soils is to apply humus (fully decomposed organic matter). It helps sandy soils retain moisture and nutrients and opens clay textured soils to air and water penetration. Remember the best functioning soils are high in organic matter and these are called loams.

For soil to perform to its optimum the organic matter content should be approximately 7%; most unnourished soils are probably around 3%. The amount of soil improver required to transform and increase the performance of your soil is therefore large. Once you have achieved the higher level, the soil will be friable and easily workable.

Peat is not a good soil improver and as such should never be incorporated within the soil. It is not fully decomposed organic matter and is very resistant to breaking down into humus. It contains no nutrients to supply plants and its water retaining abilities are very poor – peat actually repels water.

 What to add

Always add fully composted (humus) organic matter to the soil. It’s easy to identify as it should be dark brown, dry/friable and should actually smell of earth – not ammonia. Humus will provide clay and sandy soils with what they require to improve the physical properties but also provide slow release nutrients including nitrogen, phosphorus, potassium and trace elements.

The Product to use:

Organic Green Compost Soil Improver from ahs ltd.

We would like to thank George Longmuir MSc Soil Science for this insight into soils.