The Old Town site is being restored by the Patrick Geddes Gardening Club and will open in the spring.
The acclaimed town planning and environmentalist galvanised residents of the Old Town in the late 19th and early 20th century to regenerate what was then slum area.
The garden has been leased for free to Edinburgh World Heritage by the city council, which owns the building.
Cat Grant, a member of the gardening club, said: “Our long-term idea is to turn scraps of land into gardens and give people somewhere to meet and just enjoy the peace and quiet.
“We also want people to think about window boxes and using any bit of land they can.”
Edinburgh World Heritage is using a map from 1647 to guide gardeners to restore the garden.