The contest, launched this week by garden designers Diarmuid Gavin and David Domoney, will highlight the best designs in sustainable practice by UK students.
The colleges selected to enter the contest include Shuttleworth College in Bedfordshire, Merrist Wood in Surrey, Askham Bryan College in North Yorkshire, Capel Manor College in Middlesex, Writtle College in Essex, Moulton College in Northamptonshire, Duchy College in Cornwall and Chichester College in Sussex.
Entrants have to create a garden design for a small reclaimed urban space. They will have one week to build and plant the garden outside London's Earls Court ahead of the Ideal Home Show on 11-27 March.
Competition organiser Domoney said: "This is an exciting opportunity for young designers and landscapers as they embark on their career and offers a chance to bring their innovative concepts to life."
Gavin, who is judging the contest, added: "We want to celebrate the best new young talent in the country and give them a public platform to showcase their talent and earn recognition."