A team of FE Level 3 Horticulture students are designing and building the garden, to be unveiled at the Ideal Home Show on 18 March. Guidance is coming from Writtle lecturers Ben Wincott and Nigel Beckford.
Wincott, who has created several Chelsea show gardens, said: "Our design is based on a small urban basement garden retreat, featuring a roof covered with meadow grass and stunning magnolia trees to attract and support wildlife. This natural haven is full of colour to contrast against the greys of London.
"The living roof will offer the homeowner privacy from people walking past. Natural light is brought into the basement through a light well, illuminating the water feature wall alongside LED lighting.
"The green wall represents a new investigation into producing electricity from plants. It extracts electrons from water and nutrient exchange within plant roots through a carbon fibre mat inbuilt to the growing fabric. On the floor we are using sedum matting as a lawn alternative to absorb rainwater but also tolerate dry spells."
The competition pits six horticultural college teams - from Writtle, Chichester College, Capel Manor, Askham Bryan, Pershore and Shuttleworth - against each other to create sustainable urban gardens. It is organised by TV gardener David Domoney, in association with the Prince's Foundation for Building Community.
The Prince's Foundation sets clear guidelines for the garden design based on organic and sustainable principles and this year there is a new focus on education. Teams must include elements of an educational garden into the design to inspire young people to reconnect with nature.
The garden was supported by a range of companies who donated new materials and products for students to work with, including Collier and Catchpole, Global Stone Paving, Steico, Harrowden Turf, Oak View Landscapes, Hartman Outdoor Living UK, Green-tech, Lower Barn Landscape, Vincent Timber, Scotscape, Olivers Plants and Protek.