In the UK today there are essentially three main categories of topsoil available; natural 'as dug' topsoil, skip waste soil and blended soils.
Natural topsoil is highly variable in quality and availability. It can range from an acid, nutrient deficient sand, to a strongly alkaline silt loam to an organic rich peaty clay. If the characteristics of the topsoil are not suitable for the end use then widespread expensive plant failures are possible.
Natural topsoil will virtually always have a seed bank with annual and perennial weed seeds. It can often contain rhizomes of persistent weeds and grasses such as creeping buttercup, couch grass or even worse Japanese Knotweed which is regarded as one of the most invasive plants in the UK. Natural topsoil which is derived from former agricultural land may contain elevated levels of heavy metals as a result of the repeated application of sewage sludge. This is of particular importance if the topsoil is to be used in sensitive end uses, such as domestic gardens and allotments.
Skip waste soils
Skip waste soils are more common in urban areas and are a result of screening materials derived from building and demolition operations. Skip waste soils usually consist of a mixture of topsoil, subsoil, clay and numerous fragments of building waste materials - brick, concrete, mortar, ash, clinker and to a lesser extent asbestos, glass, metal, wood and plastic.
In terms of its physical and chemical properties, the material is usually extremely alkaline with a pH range of 8 - 10, saline, deficient in organic matter and plant nutrients and can often have elevated levels of zootoxic and phytotoxic contaminants. These soils can look like good topsoil, however, they often result in either plant failure or, at the very least stunted growth not to mention the consequences of having potentially contaminated soils present in a garden.
Blended soils, as the name implies are formed when two or more components are intimately mixed to form a growing medium. All of Rolawn's topsoils fall into this category. Rolawn uses natural recycled topsoils from prime arable land, recycled peat free soil conditioners and sand. Because the soils are blended from raw materials we can ensure that the same consistent quality soil is produced every time. Our soils are analysed to BS 3882:2007 and tested for PTE's (Potentially Toxic Elements).
The ideal landscaping topsoil
The ideal landscaping topsoil can be described as an organic rich, slightly acid to slightly alkaline, fertile sandy loam and free from contamination. It should be workable and available all year round. Through our many years of supplying quality products to the landscape industry Rolawn understands this and have developed our topsoils to meet these needs. As well as the attributes mentioned above Rolawn topsoils are light, friable and easy to work.
Important questions to ask when buying topsoil:
What is in the soil?
Is it safe?
Where is it from?
Will it all come from the same source?
What can it be used for?
Does it meet British Standard BS 3882:2007?
Is an independent test analysis certificate available?
Does the testing include analysis of P.T.E.s (Potentially Toxic Elements)?
Can I get hold of the same soil year round?
How is it delivered; in bags or loose?
Your topsoil supplier should be able to answer all of these questions.
For further information on Rolawn topsoils click here or contact us.