Ralph Lloyd Simon pleaded guilty to the charges in the Royal Court on Friday.
Bailiff Sir William Bailhache, who sat with two jurats, was read a list of charges including possession and supply of cannabis.
Simon was also indicted with possession with intent to supply MDMA (Ecstasy), and was also found to have cocaine and controlled drug N-ethylpentylone.
At his premises – St Peter-based Elm Farm on La Rue du Val de la Mare du Sud – Simon was also found to illegally own a Felix Sarasketa 12 gauge ‘over-and-under’ shotgun and 43 rounds of 380 calibre ammunition without holding a valid firearm certificate.
The component parts of a 12 gauge ‘side-by-side’ shotgun of an unknown make were also said to be in his possession in contravention of the law.
Crown Advocate Matthew Maletroit was prosecuting; Advocate David Steenson defended.
Simon will be sentenced by the Inferior Number on 16 February.