The group, known as Grounded Ecotherapy, come from East London’s Providence Row Housing Association and many of the gardeners have been homeless or had problems with alcohol or drugs in the past.
The team created the rooftop garden at London’s Queen Elizabeth Hall as part of the Southbank Centre’s Festival of Britain’s 60th anniversary celebrations last year. Eight members undertook formal professional training recently.
They completed the first half of the Royal Botanic Garden Edinburgh/Eden Project Certificate in Practical Horticulture, taught by Eden’s horticulturists and will complete the second half next month.
The certificate includes eight one-day gardening courses for those beginning a career in horticulture or thinking of a career change. Modules include plant health problems, soils and composting, propagation and plant maintenance.
Grounded Ecotherapy founder Paul Pulford said: "Gardening is helping us in our recovery and giving us a life. I don't have any diplomas or degrees but I will have a certificate in practical horticulture and be taken seriously as a professional gardener."
Team member Paul Davies said: "I'm a recovering alcoholic and addict so this is rehabilitating for me. This has given me structure in life, goals, aims and it’s keeping me busy. It’s something I do because I love it.