I understand I was not a big fertilizer either. But to get the Epi's to bloom I had to do something and since I am giving them a shot I usually give everybody a shot. I was surprised how fast the little thin leaf Croton that I said looked like a colorful spider plant started putting out the leaves. So I went on a search and that is when I found that they said they are heavy feeders in the summer.
Your curling leaves might be just the way that plant grows. I saw a lot of pics that the plants curled. I think it adds a certain beauty of the plant.
