Senior ADAS consultant Dan Drakes, one of the architects of the scheme, guided members through the various aspects of the Growing Media Producers Standard.
GMA chair Catherine Dawson said: "This is an excellent standard and there are real advantages stemming from the fact that it is allied to the well-respected British Ornamental Plant Producers scheme.
"For the first time, suppliers of growing media in this country will be able to demonstrate that they are producing to a high and measurable quality, using appropriate employment practices, as assessed by an external audit."
The Standard is stringent and there is no doubt that it will help to drive up quality, safety and customer confidence."