Cannabis plantations are illegal in New Zealand - unless you're one of the few companies granted a licence to grow for medical research.
Gandalf's east coast grow patch isn't one of the legal ones. He's a green fairy - someone who supplies illegal cannabis to people with health problems - and says he sells cannabis to over 1000 people who claim to have some kind of illness. He says he's coming forward now because "the time is right".
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"Patients actually are living in fear. Fear of getting caught. Fear of being stigmatised. There are so many people out there that are suffering that don't need to. I hear all their stories. I know what is going on behind the scenes," he says.
"I believe this is why I was put here on earth, was to help my fellow man and that's what I do. And f**k the law."
He took Newshub's national correspondent Patrick Gower deep into the bush to one of his outdoor plots. He has several of them scattered around outside - along with another 50 plants in his backyard.
"This is an old patch of mine. I've had it going for over 20 years," he says, and sniffs deeply.
"Oh my word, that is a lovely smell, I must say. God, I love growing this stuff."
Rose Renton is another one of the green fairies supplying cannabis medicine on the black market. Like Gandalf, Renton supplies medical cannabis to almost 1000 people.
One of those she gives her cannabis oil to is Scarlet, who suffers from chronic fatigue and fibromyalgia. Renton's oil has the same effects as Scarlet's prescribed medicine - which costs $700 for a three-week supply - except it's far cheaper, and not legal.
"She just changed my whole world," Scarlet says.
"When I got in contact with her, it's probably - besides my son being born - the best day of my life, hands down - the best day of my life.
"I just feel so much happiness. Every day I thank God for her because she's such an angel. And I'm one person."
She does this while facing the possibility of 12 years in jail for cannabis. It's legally risky, and both Gandalf and Renton have had run-ins with the law.
Police don't care whether it's medical or recreational - it's still illegal. And every year, all over the country, they take to the skies on search and destroy missions.
Spotter planes and helicopters hunt out illicit patches before ground teams are sent in to remove the plants and incinerate them. After this, a tool nicknamed the 'Dalek' sprays what's left with roundup and dye.
A few years ago Gandalf was caught by growing by police and spent several months in prison.
"Chopper flew over and then all of a sudden six police cars turned up with 12 police, just like that within minutes," he says.
"The thing that really pissed me off was all my hard work had come to nothing."
But while Gandalf and Renton might run multiple patches and supply thousands of people, it's small scale compared to the large medicinal cannabis companies starting up around New Zealand.
You can watch the full documentary on ThreeNow.