P.D. Alexander, N.C. Bragg
2011 saw the publication of a White Paper in which UK government reaffirmed its commitment to seeing a reduction in peat used in UK horticulture. The Department for Environment, Food and Rural Affairs, the Government department responsible for this issue, established a Task Force made up of representatives from across the horticultural industry (including manufacturers, growers, retailers and NGOs) to develop an agreed way forward. It was suggested by the Task Force Chairman that the issue could be broken down into 12 specific (but interlinked) projects. This paper describes the progress to date by one of these Task Force projects (Project 4). Project 4 endeavours to develop a system by which growing media materials from different sources can be assessed and compared in terms of their sustainability. The first steps of this process were to defining and qualify “sustainability”. This was achieved by identifying a number of criteria against which we would be able to assess materials (e.g., habitat damage in production, energy and water use). For each criterion, consideration was given to what it is we are trying to prevent/encourage. From this a decision tree emerged that allows users to distinguish better from poorer (in terms of sustainability) growing media sources. The accuracy of the assessment was improved by the inclusion of measurable factors in each criterion. Eight criteria have been identified allowing each material to be scored on a 0 (bad) to 20 (good) scale for each of the criteria and at the end of the decision tree, each outcome can be attributed a score. Discussion continues with regards to how best to present the information. Presenting a total score for each growing media would require the criteria to be weighted. Obviously different people will regard criteria differently in terms of their environmental values complicating the process of weighting scores. On reflection it may be more useful to simply provide the scores for individual criteria to give users as much information as possible to inform their decision making process. It is important to remember that this scheme is simply meant to give any horticultural user better information with regards to sourcing and comparing specific materials in order to make a more informed decision regarding the source-specific material they choose. This scheme has not been designed to rule in or out certain source-specific materials. One potential additional benefit of this scheme is that the horticultural users may be able to improve the “sustainability” within their supply chain by challenging suppliers to match or better their competitors in relation to specific criteria.
Alexander, P.D. and Bragg, N.C. (2014). DEFINING SUSTAINABLE GROWING MEDIA FOR SUSTAINABLE UK HORTICULTURE. Acta Hortic. 1034, 219-225
DOI: 10.17660/ActaHortic.2014.1034.26
Task Force, criteria, decision tree, peat, wood chip, wood fibre

Acta Horticulturae