Eastbourne Magistrates Court heard how on June 23 last year, police attended Victoria Mansions for unrelated matters and then became suspicious when they saw people vacating the rear of the building.
They searched Chris Southouse's flat and are said to have found 25-and-a-half ounces of dry herbal cannabis.
A search of other rooms at the property uncovered 337 cannabis plants.
Southouse, of Church Road, Cowley, Oxford, has pleaded not guilty to the production of cannabis and possession of cannabis with the intent to supply.
His defence argued that the self-employed plasterer does not live at Victoria Mansions and was in Oxford when the raid took place.
Southouse was remanded in custody. He will next appear at Hastings Magistrates Court on April 30 for a committal hearing to be sent to the Crown Court.
