A saguaro cactus (Carnegiea gigantean) is a columnar cactus that is native to the Sonoran desert in Arizona, California and Mexico. It provides cavity nesting for a variety of birds, and can be used as a food source for humans and wild animals. Because sustained freezing temperatures will quickly kill a saguaro, some gardeners must bring their cacti indoors for the winter. Whether you are growing a saguaro for permanent indoor occupation, or simply saving the cactus from freezing temperatures, the proper care of the cactus is required to help it stay healthy and thriving.
Take your containerized cactus indoors when the nighttime temperature starts to dip below 60 degrees F.
Fill a larger planter approximately three-quarter full with a mixture of cactus soil and peat moss if starting the plant inside. The planter needs to have holes in its bottom to insure that the water will properly drain out of the planter bottom. You can purchase cactus soil at most nurseries or succulent stores. The peat moss will help the soil retain nutrients without preventing proper draining.
Plant or transplant the saguaro cactus or seedling into the planter. Place the cactus roots into the planter, then fill in the soil just until you reach the cactus' green stem tissue. Saguaro cactus' green stem should never be below the ground.
Water the saguaro every 10 to 14 days. The soil should dry out completely before you need to water again. Check the soil to 4 inches deep with your fingers. If you feel even a slight bit of moisture, wait a few days to water. Even though the Saguaro is indoors, you should still follow a seasonal watering schedule. When the nighttime temperatures dip below 60 degrees F, discontinue watering altogether until the nighttime temperatures stay above 60 degrees F.
Keep your saguaro in an indoor location that is brightly lit, but has low humidity.
Take your saguaro outdoors again once there is no danger of freezing temperatures. You can take the cactus outside for several hours of bright sunshine, then bring it back indoor for the night. After two weeks, you should be able to leave the cactus outside permanently until the following winter, provided there is no danger of nighttime freezing.