The majority of cannabis now used in Wales is grown locally, according to an investigation by BBC Wales' Week In Week Out programme.
Matthew White committed suicide after taking cannabis and LSD
Many cannabis plants have also been selectively bred, to produce a much stronger drug called super skunk.
Research shows the amount of cannabis being grown is soaring and the numbers of under-16s using it is also rising.
Some believe the re-classification of cannabis to a Class C drug in 2004 sent out the wrong message to youngsters.
The amount of cannabis grown in Wales has risen from under 10% to 60% in 10 years, according to drugs consultant Liam Watson.
Police raids where cannabis plants have been seized are also on the increase, with more than 100 estimated to have been carried out in the last year.
Tests on many of these plants have found they produce a much stronger strain - known as super skunk - where the main active ingredient THC (tetrahydrocannabinol) is up to six times higher than cannabis resin.
This can be much more dangerous for younger users, who run a higher risk of developing mental health problems after smoking it.
According to the Institute of Psychiatry, around a quarter of the population are also genetically predisposed to severe psychological side effects after taking it, giving them a ten times higher risk of such problems compared with those without a genetic predisposition.
Tom Davies, from Haverfordwest, who was only 13 when he first started smoking cannabis, said smoking skunk had made him "seriously paranoid" and he isolated himself from his friends.
He also warned that the drug was easily accessible to children.
He said: "I don't smoke it any more, but I know from still looking around me that it's everywhere.
"I would say 99% of people have come across it once in their school life."
According to Home Office figures, a third of all children in the UK under the age of 16 have tried cannabis and they see it as no big deal.
Colette White said her son changed completely after using skunk
But for former school head boy Matthew White, of Cardiff, drug-taking led to suicide.
The 18-year-old hanged himself after taking LSD and cannabis in the woods where he lived with his friends in a make-shift camp.
His mother Colette White said Matthew's personality started to change drastically the moment he started smoking skunk at the age of 16.
She said: "He didn't miss school, he completed his GCSEs, he got fantastic results and we were so proud of him.
"And it only took from then, about May or June, until the October, for it all to unravel. All his previous ambition disappeared."
Mrs White said that lessons should be learned from Matthew's death and that drugs education needed to start at a young age.
Paul Flynn, MP for Newport West, believes a major re-think is needed to solve the UK's drug problem and has campaigned for the de-criminalising of cannabis for many years.
He thinks users should be treated as patients rather than criminals.
"We've had this increasing toll of wasted lives, of deaths, worse than anywhere in Europe, and we've got to say to the politicians, for goodness sake, be a little courageous, don't go for the easy headline or the quick vote."
Week In Week Out is shown at 22.35 GMT on BBC One Wales on Tuesday 12 June.