The only requirement of a salt is for it to be globally unique. If you are confident that you can achieve this requirement, by all means go ahead.
Think about it though, what exactly does your proposed scheme offer over the existing standard method of grabbing a few bytes of random data? Why do you want to piss your users of by asking for another input? Don't add more complexity for yourself and for your users. Stick with the standard method which is usually taken care of automatically by any decent password hashing library.