A Canberra man behind two northside grow houses hid one of the crops in a secret chamber beneath a garage.
The underground chamber was accessed via a hidden door, concealed by a work bench, in the garage of an uninhabited Macgregor home.
Abdul Karim Nikro's DNA was found on a cigarette butt on the floor next to the bench.
DNA and surveillance also connected Nikro to a grow house in O'Connor.
But Nikro originally pleaded not guilty in the ACT Supreme Court to charges of cultivating a commercial quantity and trafficable quantity of cannabis plants.
He switched his plea to guilty when the first count was downgraded to aiding and abetting the cultivation of a commercial quantity of cannabis at an O'Connor grow house.
Justice John Burns on Thursday found Nikro guilty of the second charge.
A police operation in 2011 uncovered 105 plants at the O'Connor property and a further 99 plants at a Macgregor home.
During the judge-alone trial, the court heard police surveillance of the O'Connor grow house captured Nikro visiting the property six times over a two-month period.
In March 2011, police raided the uninhabited house and found three rooms, a granny flat and a shed had been fitted out to grow the illicit plants.
Each room had plastic sheeting on the floor and chemicals and an illegally diverted power supply were also discovered.
Nikro's DNA was found in plastic gloves recovered from a bin and his palm print discovered inside the house.
In July, the offender was seen by police at the Macgregor grow house.
Police who raided the home in August found a hidden door leading to a two-room secret underground basement that housed a sophisticated hydroponic irrigation system.
The basement included cannabis plants, fertiliser, green vegetable matter, water tanks, heat lamps, fans, and a thermometer.
Forensic tests on a cigarette butt from the garage and the house found Nikro's DNA.
Nikro was arrested soon after in possession of keys that fit the lock of the hidden door.
The trial also heard Nikro had been linked to a grow house in NSW.
Justice Burns reserved his decision after the trial ended in May.
The judge handed down his decision to find Nikro guilty in the Supreme Court on Thursday.
Justice Burns found, in a published judgment, that the method of cultivation at Macgregor had been similar to that adopted in O'Connor.
He said it had been "improbable" that Nikro had been innocently connected with the Macgregor premises.
"It beggars belief that the accused would have been coincidentally innocently attending the Macgregor premises when, at around the same time, he was attending two other premises where he was involved in cultivating cannabis," Justice Burns said.
"The clear purpose of the wooden door giving access to the basement where the Macgregor crop was cultivated was, in combination with the bench placed in front of it, to conceal the crop.
"The accused's possession of the key to the lock to the wooden door satisfies me beyond reasonable doubt that his role in the cultivation of the Macgregor crop extended, at least, to concealing the crop."
Justice Burns said the circumstantial case against Nikro meant he could only find the defendant guilty if there was no other "reasonable hypothesis consistent with his innocence".
"I am satisfied that there is no reasonable hypothesis consistent with his innocence.
" I am satisfied beyond a reasonable doubt that he is guilty of the offence."