He initially grew vegetables but turned to cannabis to alleviate his arthritis. But, just like mild-mannered Walter White in the hit TV series, Collier began making big money and embarked on a life of crime.
His family business, AJ Motors, was transformed into a thriving drugs empire with production on a commercial scale.
A court heard Collier, of Plymouth, Devon, had 71 cannabis plants growing in a sophisticated set-up in an outbuilding at the garage.
His family knew nothing about his illicit business until police raided the premises in May 2016.
They found a book with records of crop weights dating back to 2011.
Julia Cox, prosecuting at Plymouth Crown Court, said the drugs seized had a street value of between £43,000 and £51,000.
Over the years the total value was over £1million but police accept Collier was paid far less than that.
Ali Rafati, defending, said Collier, married three times and with four children and eight grandchildren, was ashamed of what he had done.
He added: “The quantities escalated and there was a financial element which was attractive when his business was not doing so well.”
Jailing him for three years and four months, Judge Paul Darlow said: “You ran a relatively sophisticated operation producing commercial quantities.”
The judge ordered £68,000 be confiscated under the Proceeds of Crime Act.
Collier admitted two counts of producing a Class B drug but denied supplying it.