This is, without a doubt, one of the the most commonly asked questions pertaining to locks. Incidentally, it has the simplest answer: Roots knot up on their own. The new growth of locks do not require any sort of manual manipulation. They will tangle up all by themselves.
This can seem false to a newbie, though, because locks never knot tightly against the scalp, no matter how much maintenance is done. There will always be 0.5-2 inches of loose hair between the tightly knotted part of the lock and the scalp. This area of looseness allows the individual hairs to move around and breathe. With very few exceptions, manually manipulating loose roots with a maintenance method to try to get knots closely against the scalp can result in redness, bumps, irritation, and hair breakage.