So sorry but I have not heard of a fingernail plant and could not find any information about such a plant. Perhaps you meant the finger palm? If so this slow growing fan palm is a good choice indoors or outside in a warm climate such as zones 20-24. It needs regular water so poke a finger into the soil and water when the top inch is dry. The finger palm also needs shade outdoors in the afternoon and bright but indirect light if grown as a houseplant.  If your plant is not a type of palm tree please send a photo and I may be better able to identify and advise you about the plant. Keep growing, Marianne Binetti