Developing a methodology to replace peat in UK horticulture with responsibly sourced alternative raw materials

In the UK peat has been used as a raw material for containerised plant production over the last 60 years. There has, however, in more recent times, been a push from both the UK Government and consumers to expand the list of materials available for containerised production, because of environmental concerns surrounding peat harvesting. This has presented the industry with a significant challenge, due to the multiple benefits of peat, but also provides security by not being solely reliant on a single raw material. Over the last 10 years growing media manufacturers have played a crucial role in sourcing and conditioning four main types of non-peat materials: coir, wood fibre, bark and green compost. Increasing the use of these materials will move the UK towards responsibly sourced growing media (RSGM), but a number of significant barriers exist to widespread adoption and use by growers. This paper describes part of an integrated experimental and on-site testing program of work that has been developed to promote the transition to RSGM. The method advocates a move away from iterative stand-alone 'look-see' trials towards a novel innovative, predictive 'unifying multivariate model' which will identify high performing blends. The blends are being tested for the main users of growing media in the UK, which includes hardy nursey stock, bedding plants, soft fruit, top fruit, vegetables, protected edibles and mushrooms. Where appropriate, propagation and main growth phase stages are evaluated. Shelf-life performance of marketable products are also quantified. The ability to target desirable physical or chemical characteristics and predict blend performance from a range of raw material types and sources will not only be cost effective, but will also accelerate the identification and use of new raw materials for use in horticulture plant production systems.