Roots and Shoots provides vocational training in horticulture, floristry and retail, together with functional and life skills, to disadvantaged young people with additional needs.
The new building, which sits alongside Roots and Shoots' half-acre wild garden in Kennington, has been designed by Hudson Architects of Norwich. It uses natural materials, with a cedar-clad exterior, corten steel tower and interior lined with birch faced ply and floored with oiled oak.
When complete, the building will be available for event and meeting hire, providing additional income for the charity.
Liz Peace, chair of property industry charity LandAid, opened the facility, after LandAid gave a grant totalling over £150,000 to the project. Others such as Wacoco, The Ecological Building Society and The Royal Bank of Scotland, together with a number of smaller funders, also donated. The total building budget was £218,000.
"We have a beautiful building that is the 'Jewel in the Crown' for our charity and we are enormously grateful for LandAid's as well as our other funders' support," said Linda Phillips, director of Roots and Shoots.
"It's the green heart of Roots and Shoots and will allow us to teach our young people the green skills they need to make them more employable. It is also a wonderful resource for schoolchildren and the local community."