Garrett, who now oversees the East Sussex garden following the death of plantsman Christopher Lloyd in 2006, makes 20 tonnes of his own compost mix annually. This is comprised of a peat base, Dixter's green waste and Melcourt chipped bark.
He told Howard Nurseries Sustainable Ornamentals Production Focus last week: "We're now going to cut peat completely, having spoken to Melcourt. I think this will give us the final push."
Garrett said Dixter produces 70 per cent of its own plants for sale and sources 20 per cent from Howard Nurseries. In the past 12 years he has trebled income from Dixter's nursery.
At the event, Melcourt technical director Catherine Dawson revealed Melcourt will launch Sylvagrow, its first consumer bark compost at Glee on 15-17 September.