Hi Loolah. What kind of medium are the plants in? If there are roots drying and withering it could be lack of humidity/moisture compared to what they were used to before you got them. It could also be due to not watering enough. Can you provide some photographs? As far as a watering schedule, every growing situation is different. You have to go by the conditions of your particular plants. It is best to water when the medium approaches dryness and this can differ widely depending on the medium, humidity, and air circulation where you are growing them.