Hi! I have 4 phalaenopsis that are in dire need of re-potting. (I didn't know much about orchids till this board). Where I live I can't find good media at the moment, guessing because it's not spring yet? At walmart I found a bagged mix. So here is my question do I used the bagged orchid mix or do I wait till the end of march for the orchid show and buy a high quality mix?