When asked why he used acid, Knights told Maidstone Crown Court: "I watched Breaking Bad and in my madness at that point I thought that the only way I could get rid of him was to do what they did in that. It was the only thing I could think of.
"I looked up on my computer what acid it was and it was sulphuric acid, which is what I had used in an attempt to make amphetamine, and what kind of plastic you have to put it in.
"The wheelie bin was the right plastic. I got the wheelie bin from down the road….I don't know what I was thinking at this point. My mind was just everywhere. I brought it back to the house and put it in the conservatory.
"I put it on its side in the kitchen….Then I pushed and pulled Ginger into the wheelie bin. While I was doing that his shoes came off. That's why he wasn't wearing any.
"Obviously I wasn't thinking straight at all. I didn't put a gas mask on or anything like that. I got acid which was already in the house and poured it on top in the bin until I couldn't breathe anymore.
"Then I shut the conservatory doors and I left. I think I went upstairs and I was just crying."
Jurors heard how Knights accepts killing Stephen and trying to destroy his body but denies murder.
He claims he felt threatened by the dad leading up to the stabbing after he told him he wouldn't sell cocaine for him anymore.
Knights also told the court Stephen sent an "enforcer" round to his home around a month before the killing after he bought drugs from someone else.
And he claimed to jurors the dad had attacked him when he again refused to sell drugs.
Knights said: "He pushed me against the wall and punched me in the stomach and winded me. He tried to put his hand around my throat but I was shouting at him to leave so he left.
“There was nobody else at home. I felt like Ginger was really trying to take advantage of me.
"After the second incident it was like I didn’t want to be at home any more. I felt in danger and I felt like he could do this whenever he wanted to do it.”
'I PUT THE KNIFE INTO HIS HEAD'
On the night of the killing, Knights armed himself with the commando knife after "angry and intimidating" Stephen went to his home.
The teen told jurors a "struggle" ensued and Stephen tried to stab him as he pinned him down.
He added: "I had the knife in my left hand, I pulled his body against me with my right arm and put the knife into his head.
"I just had to go for the first thing I saw. At the time I genuinely thought he was going to kill me."
Knights claimed he was left crying, shaking and vomiting as he attempted to clean the blood up.
The court was told he first tried hiding Stephen's body with a towel, bedsheet, plastic bag, rug and a military bag before settling on the bin with acid.
He then binged on medication, alcohol and drugs while partying with pals as Stephen's worried family reported him missing, it was said.
His decomposing body was eventually found by cops two days later on October 25 in Knights' dad's conservatory.
Knights is accused of murdering Stephen in a bid to steal £2,500 worth of cocaine, which he denies.