Police responding to a report of a rave being set up at Moulton Marsh searched a man and found he had cannabis in his possession.
Spalding magistrates heard police went to Middle Marsh Road just after 10pm on March 30.
Marie Stace, prosecuting, said Mark Stockdale was told he was going to be searched and produced a small plastic tub containing cannabis bush.
Stockdale told police he was going to smoke it.
Solicitor Anita Toal, mitigating, said Stockdale had a history of drug problems, but his last offence was in 2009.
He had worked hard with the probation service to cut down on drugs. In the past he used ketamine, LSD and more serious drugs but now only cannabis.
Mrs Toal said his last offence was in 2009.
Stockdale (27), of Rowan Avenue, Spalding, was fined £65 and ordered to pay £85 costs and a £20 victim surcharge. Magistrates ordered destruction of the cannabis.