With rounded leaves that look just like a watermelon rind, Watermelon Peperomia does best in well-lit rooms (but no direct sun) with a thorough watering when the top inch of soil is dry. As is true of most house plants, good drainage is a must for this peperomia, and periodic misting will keep it happy. Growing to about 12 inches tall and wide, Watermelon Peperomia may take its time reaching its mature size, especially if it's not getting enough light.