Cacti are among the most fascinating groups of indoor plants. The numerous variations in color, size and form ensures that any cacti collection will be unique. Cacti can grow in spots where many other house plants will not. They can stand dry air, relatively high or low temperatures and neglect—a good quality for people who forget to water their plants
Light and Temperature
Most species of cactus require bright sunlight to grow well. Windows facing south provide the most sunlight, while windows facing west usually offer some direct sun for at least part of the day.
Proper temperatures for raising cactus vary with the season. Arid cacti tolerate temperatures of 32 to 37°C during the active growing season. Dormant cacti (months of October to February) do best at temperatures from 7 to 19°C. The cooler temperatures develop sturdier plants and encourage the formation of flower buds. Cool winter temperatures are not a necessity for cactus plants, but these conditions approach the environment in which cacti usually grow.
Like other types of house plants, cacti need fertilizer but in smaller amounts. From spring to fall, they can be fertilized every two to three months with a low nitrogen fertilizer such as Schultz Cactus Plus 2-7-7. Do not fertilize newly repotted plants, unrooted plants or plants going through a dormancy period.
Good drainage is essential in any soil mix, yet the soil must also have moisture retention properties, along with adequate nutrients. A general growing medium, such as Schultz Cactus and Succulent Soil, consists of one third peat moss, one third organic material and perlite and one third sharp sand.
Watering properly is one of the most important factors in cactus culture. Soil mixture, container size, drainage, temperature, size and type of plant all influence water use, therefore no absolute schedule can be giving for watering.
Careful observation is the best way to determine a plants water needs. During the active growing season (spring-summer), water approximately once every three weeks depending on the temperature. The soil should be thoroughly wetted at each watering and allowed to dry before water is added again. Dormant cacti need less moisture. During the winter months, watering once every 5-6 weeks is sufficient.
Cacti should be repotted as needed, rather than on a regular schedule. Repot if the cactus plant is within a quarter inch of the container wall. Repot into a container only slightly larger than the present one. Repotting into a container too large may lead to a tendency to over water.
When transplanting, wrap a strip of rolled newspaper around the plant to maneuver it into its new pot. Set the plant in the new container at the same level it was originally growing and fill around it with damp soil. Wait several days before watering so damaged roots have time to heal.