Soil Types and Soil Management

A good quality soil or growing medium is the first vital step to healthy plants. Not only will plants thrive but also weeding and maintenance will almost certainly be easier, saving you a lot of time in the long term. Soils vary tremendously and in most gardens it is beneficial to improve the soil. Ideal times to tackle soil improvement are the spring or autumn.

To identify your soil texture, moisten a handful of soil and roll it in between your hands. If it holds together well and is sticky to the touch, then it is a clay soil.

Clay Soils 

Clay soils are heavy and difficult to work. They bake hard in dry weather and, although they tend to hold more water than other soils, it is often difficult for plants to take up the water. Clay soils warm up more slowly in the spring, which can delay seed sowing, but they tend to retain warmth at the other end of the summer.

To improve a clay soil, work in some fine grit or a grit/sand mix and incorporate organic matter, such as composted bark, peat or garden compost. This will assist in creating a good structure to the soil, making it more crumb-like and less sticky.

The pH (Acidity or Alkalinity) of a soil will determine how available various nutrients are to plants and which plants are most suited to grow in your garden.

If the soil is extremely heavy as often is the case in new housing developments, when frequently the layer of topsoil is thin to the point of being almost non-existent, you can purchase bags of topsoil to give you a quick fix and enable plants to get established. You can then continue to improve the soil over time.

Sandy Soils

Sandy soils will not hold together when moistened and will feel gritty when rubbed between the fingers. On the plus side they are easy to work and they warm up quickly in the spring making them more conducive to earlier sowing, however sandy soils do not hold water or nutrients very well.

The addition of organic matter will help the sandy soil to be more water and nutrient retentive and in order to get the most out of plants growing on them, ensure you water regularly in dry spells and use a slow release fertiliser that contains a wide range of nutrients such as Vitax Q4 rather than, say, applying growmore, prior to sowing or planting.

It is good practice to apply a soluble fertilizer such as Miracle-Gro or Phostrogen on a regular basis to prevent plants becoming nutrient deficient.

Soils containing a high proportion of silt 

Soils containing a high proportion of silt will be ‘silky’ or ‘soapy’ when moistened and rubbed between the fingers. They are dusty soils and can form surface ‘crusts,’ as the silt particles tend to stick together. Rain tends to puddle on the surface and seedlings can have a tough time pushing through the silt surface layer. The addition of organic matter will also improve these soils. 

Another factor to bear in mind is how acid or alkaline (soil pH) your soil is. Some plants like Azaleas, Rhododendrons, Camellias and most Heathers, will not tolerate an alkaline soil. Details of plant preferences will normally be given on the label but if you are unsure, check your garden soil using a proprietary pH soil tester. This is very easy to use and will give you an indication of how acid or alkaline the soil is in a matter of minutes and could save you a lot of disappointment in the long run.

The ‘ideal’ pH is slightly acid and this will enable a wider range of nutrients to be available and a broad range of plants to be grown. If you find your soil is alkaline and you wish to grow acid-loving plants such as those listed above, the best option is to grow them in containers filled with ericaceous compost. If your soil is very acidic, use garden lime as directed to make it more alkaline.