Judge Andrew Wilson said: "The main review has finished. At the moment the RHS is using the existing system but trialling the new system. The main difference is what the RHS thinks a gold or silver gilt is.
"Rather than saying is this a good garden and it gets a gold, you say does it fit the criteria of a gold medal garden, which is much more transparent. It's not set in stone and can be discussed.
"The key criteria in some ways follow closely what the judges already look at - plant quality, association of plants, choice of construction materials, quality of finish. But instead of saying this is a good-quality finish, you have levels to differentiate gold and silver gilt - like marking a student project from A-C."
RHS shows director Stephen Bennett added: "We are building pools from which to draw people by identifying those with appropriate experience and knowledge and putting them through training courses."