Nelly has banned marijuana from his tour bus because of his young son.

The Hot in Herre hitmaker admitted life on the road is much different now because wife Ashanti and their 12-month-old son KK have been joining him so things are much more calm.

He told People magazine: "They joined me. They've been on the road a lot,.

"When Shan has a show or something she has to tend to, obviously I don't have a choice, she takes him with her. She's an incredible person already, so to watch her go through motherhood for the first time is really a joy to watch, man.

"It's dope, man. It's different on the bus, I'll tell you that. There's no more weed smoking and no s*** like that, you know what I'm saying?"

"That's gone."

The 50-year-old rapper - who has Cornell and Chanelle from a previous relationship and also adopted his late stepsister Jaqueline Donahue's children Shawn and Sydney - loves seeing Ashanti with their son, particularly because he knows how lucky they are to have children.

He said: "Everybody doesn't get a chance to be a mother, everybody don't get that chance, and that's something that I did not realize until me and her got back together, so to speak.

"There's so many women out here that do not get a chance to become mothers, and it's not by their decision. Things could be medical, it could be health, it could be some other different things as well.

"But to watch her eyes light up every day and the joy with him -- he's the splitting image of her, too -- it's great."

Nelly and Ashanti, 43, recently reflected on their different approaches to parenting.

Admitting she is "very mama bear-ish", Ashanti told People magazine: "For me, obviously this is my first child.

"We have to boil everything and sanitise everything. Everything has to be organic. His sheets are organic, his socks, food-grade silicone, everything. I'm just very, very protective."

Nelly said: "I think I understand a little bit more about children. They learn more on their own."

The Dilemma hitmaker believes his wife is "motherly overprotective" but he is more "safety overprotective" and insisted it is important for parents not to do everything for their children.

He said: "I know if they don't learn certain things by the time they reach a certain age, we're going to pay for that, I promise you. And it's going to backfire on us in a big way."

He jokingly added: "Right now I know she's loving it, but that boy turns 17 or 18, she going to be like, 'Why is he acting like this?' And I'm going to ask [Ashanti's mom and manager, Tina Douglas] for that video of him being three. And I'm going to say, 'You see this right here when he used to...'"

But despite their different approaches to parenting, Nelly thinks Ashanti is a "great" mom to their son.

He said: "I have no complaints. I wish all mothers could see the way that she get down a little bit. You wish every kid had that type of love."