|Le'Veah Herbert died at the age of just eight months old|
Shannon Whittaker, 18, had brought her in beside her at 4am - having earlier drunk wine and brandy as well as smoking cannabis with neighbours.
Miss Whittaker woke up at 1pm later that day to find the youngster unresponsive.
Paramedics dashed to her terraced property in Gorton, Manchester but Le'veah was pronounced dead at Royal Manchester Children's Hospital.
The infant's cause of death is unknown but tests showed she had traces of drugs in her hair consistent with her being "exposed" to the drugs or "ingesting" them at her home.
Police found a variety of drug paraphernalia in the family's living room.
Both Miss Whittaker and Le'veah's father Linton Herbert were questioned about the tragedy but no action was taken against them.
At the Manchester hearing, Miss Whittaker, now 21, broke down and wept as she relived the tragedy which occurred on July 5 2014.
She and her daughter - who had only moved into the property the previous March - were known to social services but officials said Le'veah was "thriving" and Miss Whittaker was a "credit to young mothers."
Miss Whittaker said: "I had a social worker and a Barnardos worker, and Le'veah had her own social worker from before she was born.
"She had fallen off the bed one or two times before but I had always been awake when that happened.
"She had never hurt herself from doing it. She wasn't crawling she was just rolling around."
She added: "On the fifth it was a sunny day and my neighbours came over and we were just chilling together.
"At some point we had a joint and some wine.
"We were just chilling and then at around 9 or 10pm Linton put Le'veah to sleep in her bed and went out.
"I stayed up just chatting and stuff and then at three or four am the neighbours went home.
"We drank brandy and wine and yes I did smoke some cannabis but that was downstairs.
"Then I went upstairs and took Le'veah out of her bed and into mine.
"I fed her some tuna and pasta out of a baby jar and I was checking on her all night.
"When I woke up at 1pm I realised that Le'veah wasn't in the bed and I just panicked straight away.
"She was on the floor by the side of the bed where I had put some washing. She was under the bag of clothes."
Mr Herbert said: "I did stay in the house quite a lot of the time. Le'veah did fall out of the bed once or twice that I saw.
"On the day she died I was at the house in the day and was just doing what we usually do and then about 9pm Shannon's two friends came over.
"At 10pm I left to go out to got to a party. I stayed at my mum's house because the party was close to her house.
"I got a call in the morning telling me what happened. Shannon seemed fine, she was with her friends.
"I think they had drunk two bottles of wine or something and there was brandy."
When asked how his daughter came into contact with drugs, Mr Herbert added: "I don't know really, maybe it was on something she had touched that the drugs had been on that she got hold of.
"I don't know that's the only way I can explain it. Possibly from the surfaces. We didn't smoke cannabis in the house. I didn't ever smoke cannabis in front of her and I didn't take cocaine in front of her either. " Receive Instant News Update Via BBM: D3EDEFDF...Click HERE for Details. Share your story with us: email@example.com PLACE YOUR TEXT ADVERT BELOW:>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> How I TOTALLY Got Rid Of my POT BELLY,excess Fat and Overweight In just 2weeks.. Click HERE for Details. Warning To Men: This 3 Foods Is Killing Your Erection. Click Here To Know Them