Sourcing quality Topsoil

Quality Topsoil is the foundation of a healthy garden and other soft landscape projects. It is responsible for the establishment and sustained growth of lawns, trees, shrubs, etc. that have been carefully selected, approved and installed. If the incorrect topsoil is used, plants can quickly show their disapproval and the consequences can range from having to carry out remedial work to starting the project again. In any event, it will cost time and money, so it is essential to get it right first time.

Every project is unique. Topsoil must be selected with thought and care and not by automatically using the site's existing topsoil or the first source of imported topsoil you located.

Before considering importing topsoil, any existing site topsoil needs to be properly assessed. This is achieved as part of a Soil Resource Survey, which evaluates the quality, quantity and suitability of a site's soil resources (topsoil and subsoil) for the intended landscape project. This would usually be undertaken by a Soil Scientist, and involves a review of the intended landscape scheme, a site investigation, and laboratory analysis of soil samples. The findings are presented in an interpretive report, with recommendations for the recovery and re-use of the site soils.

Homeowners may choose not to employ the services of a Soil Scientist, but they should at least conduct an assessment of what they currently have to work with and what they wish to achieve.

Important questions that should be answered by the Soil Resource Survey or homeowner's assessment are:

• What are the needs of the planting scheme?
• Does the site drain - i.e. what are the drainage properties of the site subsoil?
• Will the site provide sufficient topsoil for the landscape scheme?
• Is there space to store the topsoil?
• Will the topsoil be stripped and stored in winter or summer?
• Will the topsoil be respread in winter or summer?
• Is the topsoil suitable for re-use?

If the site topsoil is unsuitable for re-use, or there is a shortage of topsoil, imported topsoil will need to be sourced. This is usually achieved by including a Topsoil Specification within the Landscape Architect's Soft Landscape Specification tender document.

Rolawn would like to thank Tim O'Hare, Partner and the Principal Soil Consultant of Tim O'Hare Associates LLP, for his contribution to this section.