Tracking peat usage in growing media production – method statement
Updated 18 November 2020
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Background
Defra, the Growing Media Association (GMA), Horticultural Trades Association (HTA) and the Agriculture and Horticulture Development Board (AHDB) are co-funding a monitoring project. The project involves measuring and tracking the proportion and volume of ingredients used in growing media sold by manufacturers to the UK’s retail, professional and export sectors.
The current project covers the years 2018 to 2022 and follows on from a previous project funded by the same consortium covering 2011 to 2015. Prior to that, until 2009, projects were sole-funded by Defra to monitor the composition of growing media.
Differences in sampling and methodology mean that data before and after 2009/2011 are not directly comparable. The main difference is that green compost manufacturers are no longer included in the survey. Data was sought from 191 green compost producers (249 sites) in the 2009 survey. The 2009 data on the volume and composition of growing media was compiled under Defra project SP08020. Earlier data (2005 and 2007) was compiled in project WC04019.
Research methodology
Data on the volume and composition of growing media supplied to the UK amateur and professional use horticultural markets was collected by means of a self-completion form. An independent consultant, Paul Waller Consulting (PWC), was engaged to ensure the confidentiality of information collected. Data was provided by growing media producers on a confidential basis.
Data was collected each year for the previous calendar year, apart from 2016 and 2017 (where no data was collected) and 2018 (where the data was collected in 2020). The form was administered to 30 growing media manufacturers which account for the majority of UK growing media supply, and 27 returns were received for 2011 and 2012, 26 returns for 2013, and 24 returns for 2014.
When the study resumed in 2020 some smaller businesses declined to participate, and one business joined the study. There were 20 returns received for each of 2018 and 2019. Given the small size of the businesses who are no longer participating in the study this change is not believed to have had a material impact on the findings.
The 2020 data will be collected in 2021, 2021 data collected in 2022, and finally the 2022 data collected in 2023. A more detailed methodology is included in the ‘Growing media monitor: trends in the composition of UK growing media supplied 2011 to 2019’report on GMA’s website. Consolidated datasheets for the 2011-2015 and 2018-2019 data sets are published on the GMA’s website and also here.