Three awards categories will be added to the annual project award, which currently examines a full presentation plan, planting schemes and client brief. The new categories will be photographic, creative writing and graphic illustration.
SGD student judging panel chairman Stephen White explained: "It struck me that the competition was limited to students at the end of their course.
"I am keen to extend the skills of students and I felt we ought to be looking at all students being able to have a go at some aspects of the competition."
The awards categories will be launched in January 2010 and will run at different stages throughout the year.
"I hope that will encourage student members to get involved," added White.
The winners of this year's competition were announced during the autumn conference, with first prize being awarded to Oxford College of Garden Design student Sarah Naybour.
The judges — who included Mike Gerrard and Caroline Davy — compared entries from 13 different colleges. Naybour's design was "really exciting and dynamic", White said.
Merrist Wood College student Anita Foy was awarded second prize, while third prize went to Iris Worker, who studies at Robin Templar-Williams' Garden Design School.