Nearly anyone wondering how to grow succulents indoors can look no farther than their own grandmother's windowsill, which probably boasted at least one. Because of their incredible shapes and forms, and tolerance of moderate light, low humidity, and weeks of neglect, succulent house plants such as a mother-in-law tongue or snake plant (Sansevieria) or florist's Kalanchoe have graced many a living room corner or kitchen window, or a gifted Christmas cactus (Schlumbergera) that simply won't die.