The Christmas cactus (Schlumbergera bridgesii) is a popular, long-lived tropical epiphytic plant, not a desert cactus, requiring indirect light, high humidity, and moderate temperatures (65-75 degrees). To trigger blooms, provide 12-14 hours of darkness and cooler nights (50-55 degrees) in autumn. Water when the topsoil is dry, allowing for good drainage, and fertilize monthly from late winter to summer.