The industry has to follow tight standards with products checked at all stages of production. Growing media need to be entirely traceable and free from potentially dangerous contaminants.
"There are questions about green waste and risks of contamination," said JB Shropshire & Sons technical director Liz Johnson.
Speaking at the International Peat Society and Stockbridge Technology Centre conference last week, she said: "Food safety is a priority. Any product must be safe for the user and consumer."
She added: "Growing media needs to be free from pests, weeds, diseases and pesticide residues, with no contaminants that make it dangerous for use. It also needs to be free of sharps and produced from approved inputs with complete traceability."