According to this trichologist (hair doc) blokie in my mag....you should wash your hair everyday....whatever type of hair you have - greasy, dry, combo...
just as you wash your face everyday, you should wash your hair - this chappy says. Maybe try that and see if it helps.

I use an organic shampoo/conditioner - MOP (modern organic products) its called. It smells lovely, oh and is good for all hair types. However, My hair tends to be dry.