In a talk on what sells, he said the trend has grown on the back of the drive for locally grown edibles.
He said another significant trend was for wildlife and bird care: "Consumers want to attract wildlife into the garden and 59 per cent of people feed the birds in the garden."
Garden centre catering has become so crucial it can drive up to 25 per cent of sales. Of 36 million visits to garden centres, one third were made because the customer wanted to visit the restaurant.
The last big trend, he said, "has to be plants", which have seen stable sales despite the overall market decline.
They are, he said, the real unique selling proposition (USP) for garden centres.