I have 3 Passiflora, which I purchased off of Ebay in 4-inch round plastic pots which I have been growing indoors. They are not doing well. One plant has lots most of its leaves. I'm having a hard time keeping them watered. I don't know what type of planting medium they are in, but they dry out very quickly. I know they need warmth and sunshine, but right now is not the time to put them outdoors. Does anyone have any suggestions on how I can keep these plants alive ?