The BBC2 show attracted 1.9 million viewers - a nine per cent share - when it broadcast four shows at 8pm in mid May.
Fisher Tomlin said enquiries to his London College of Garden Design quadrupled in the week of broadcast ahead of the RHS Chelsea Flower Show in May thanks to runner-up Paul Harris being trained at the college and referring on queries.
Dougal Philip, another RHS judge, agreed that the show was a success and said it should come back. The BBC declined to comment.
Meanwhile, the RHS Chelsea Flower Show 2016 is set to see the return of Hugo Bugg for the Royal Bank of Canada and Charlie Allbone with Husqvarna.
Other sponsors set to come back are M&G, Laurent Perrier, Brewin Dolphin and The Daily Telegraph.