Peat-free growing media mixes
Designing sustainable alternatives to peat
It is possible to design peat-free mixes that have similar characteristics to peat-based products.
However, it has not been a straightforward process. Although sustainable raw materials exist, a blend is often necessary to produce a high-quality growing medium that is a suitable alternative to peat.
ADAS Horticulture have been conducting intensive research on peat-free growing media and have now developed an innovative new approach to designing peat-free mixes.
Trials prove high performance of peat-free mixes
Between 2015 and 2019, the AHDB and Defra provided funding for ADAS to carry out a large programme of peat-free growing media trials with commercial growers on a range of crops including bedding and pot plants, hardy nursery stock, protected edibles, soft and top fruit, and salad crops.
“These trials showed us and the growers than we can produce peat-free mixes that perform as well as peat,” explained Dr Jill England, ADAS Head of Horticulture.
“Most peat-free growing media mixes are produced by blending a mix of materials, predominately wood fibre, bark, coir and green compost.
“It is important to get the ratio of materials used right as this will impact on the quality and characteristics of the growing media. ADAS has developed a new rapid-screening and blending programme to help do just that,” she added.
Dr Andrew Watson, Quantitative Horticultural Consultant at ADAS, said,
“Our research has identified three key physical properties as indicators of growing media performance: available water holding capacity, bulk density and air-filled porosity. We can analyse the individual raw materials for these physical properties and use this information to recommend a suitable mix of material to produce a high-quality growing media mix.”