Dublin Children's Court heard that the 17-year-old boy's family have had to take out loans to clear his debt which "runs into thousands of euros".
The teenager, whose drug problem spiralled out of control following the death of his father, pleaded guilty to possessing cannabis at his south Dublin home, on November 30, 2011.
Garda Marcus Ryan said cannabis worth €10 was found in the teen's bedroom. A cannabis plant with a street value of €200 was also found.
The court heard that the teen "had built up serious debts which were being called in". Instead of increasing his debts "he decided to grow his own", Gareth Noble, defending, said.
Judge Ann Ryan adjourned sentencing until January 10.