When an estate agent went to view a house, he found a cannabis cultivation with a potential value of £3,000 in a cupboard.
Police found 33 plants, a lamp and a thermometer in the property at Craigend Road, Stow.
Gordon McDonald admitted producing cannabis at the house between July 2, 2012, and January 9 this year.
“The house was subject of a let and was being viewed by a potential new renter,” explained prosecutor Graham Fraser at Selkirk Sheriff Court on Monday.
Mr Fraser told the hearing: “A representative of the estate agent was going round the premises and went into an upstairs bedroom, and in a walk-in cupboard found green plants in pots with a lit lamp above them.
“He suspected it was a cannabis cultivation and told his boss, who contacted police.”
Officers found a letter addressed to the accused on the doormat and he was contacted, attending voluntarily at a police station.
Mr Fraser said police found 33 cannabis plants, along with about 15 large plant pots filled with compost in an upstairs bathroom.
McDonald, 36, who lives at George Grieve Way, Tranent, said he grew cannabis to self-medicate, as he suffered from cluster headaches.
Mr Fraser said the plants could be worth up to £3,000, or as little as £900.
Defending, Iain Burke said the value was much nearer the lower end of £900.
He said his client had been growing the plants as he suffered from migraine-type headaches for which he had previously been prescribed injections and painkillers.
Sheriff Kevin Drummond deferred sentence until July 8 for reports, commenting: “The scale of the operation is significant, as is the period over which it was carried out.”