Firstly, you shouldn't be using lemon juice. It makes hair brittle.
There should always be some loose hair on top of your scalp. This is how the roots keep locked. If there is a lot of loose hair then maybe the pressure of your shower is keeping it from wrapping up in the dreads before a certain length (just a suggestion).
Wish I could of been more help. You could post some pictures so we have a better idea of what you are dealing with.