PAUL Underwood disguised his illegal trade by making his text messages look like harmless shopping lists but detectives uncovered their dark double meanings.
He told one customer he had "top food" and asked them if they wanted "a leg of lamb".
Drug squad experts realised the "food" was heroin and "leg of lamb" was rhyming slang for a gram.
Other texts disguised drug deals by referring to bags of heroin as "bagels" and bottles of methadone as "greens".
They also used slang to define different quantities with Oscar being an ounce and Hen being an eighth, an abbreviation of Henry VIII.
The dealer's bizarre private language referred to cannabis as Sergeant Bash – rhyming slang for hash.
Underwood and his lodger Mark Wilson were caught with £2,250 of heroin and £1,280 cash when police raided his flat in Barnstaple, a year ago.
They also found a flourishing skunk cannabis farm with a £7,500 crop and harvested leaves and buds ready for use, Exeter Crown Court was told.
Underwood, 52, and Wilson, 44, both of Castle Street, Barnstaple, denied possession of heroin with intent to supply and Wilson denied possessing methadone with intent to supply.
They were both found guilty after North Devon drugs liaison officer Detective Constable Jane Dyer, gave the jury a crash course in drugs slang and deciphered the messages on Underwood's phone.
Underwood was jailed for three and a half years and Wilson for two and a half by Judge Erik Salomonsen.
He told them: "The texts showed very clearly what you were doing and that Underwood was not only producing but supplying cannabis to others."
The jury was told heroin, methadone, and cannabis were all supplied out of the Castle Street flat for several months.
The pair claimed they had bought them in bulk for their own consumption and had no intention of passing them on.