The Phoenix High School in Shepherd's Bush is the only secondary school selected to exhibit at this year's show.
Designed by sixth-form students and their teacher Vanessa Hodder, it will depict an 18th-century market garden, recreating the small farm the school runs in the middle of the White City Estate.
A selection of plants and vegetable from around the world will be including, many grown from seed by the students.
Mitie, Taylor Woodrow and Quadron idverde all have long-term connections with the school, and were delighted to be able to support the project. Quadron has assisted the school with the project management, quantity surveying and construction design details for the garden, and will also be supplying and laying the turf for the show garden; the Quadron team includes an ex-student of the school.
Mitie, whose apprentices have carried out work at the school farm, have sponsored the materials and will be supplying labour to help build the base, planters and pathways for the show garden.
Taylor Woodrow, whose staff from the Cross Rail project at Old Oak Common regularly volunteer at the school's farm, are also helping with the construction of the show garden.
Jan Parnell, head of the sixth form, said: "Without the expertise of the contractors on board I don't think we would have been able to contemplate a project of this scale. It is a fantastic opportunity for our pupils to get practical hands on experience."
Quadron also manages the RHS Re-use scheme for Hampton Court Palace Flower Show, which sees plants and materials used in the show's gardens collected and distributed free of charge to local gardening projects, rather than go to landfill. The market garden's materials will go to several beneficiaries including nearby Wormholt Primary School, where a new growing area will be created. Currently the school's open space is all Tarmac.
Quadron MD Clive Ivil said: "It is a pleasure to be able to support the Phoenix School with this project. To be selected to exhibit their garden at the RHS Hampton Court Show is testament to the skills the students have developed in a range of disciplines from design and planning to growing and planting.
"We look forward to seeing Phoenix High School's completed garden and will ensure that the plants and materials used will benefit a local growing project as part of the re-use scheme Quadron idverde co-ordinates in partnership with the RHS after the show closes."
Cultivate London have also donated plants to the garden as have Hammersmith Community Gardens and Salt Yard Restaurant Group.