If you're having issues with dandruff, vinegar is a good natural solution for your hair. All you need to do is mix equal parts water and vinegar in a spray bottle and wash your hair like you would normally. After you finish, spray the solution around your roots and massage it in. This should help balance out your scalp and prevent excess dandruff from forming. It's also good for killing bacteria.
In addition, you should notice a considerable improvement when it comes to an itchy scalp. Use either white vinegar or apple cider vinegar, but be aware the latter will leave you smelling like apples.