Evoking scenes of the desert and rocky landscapes, cactus is a water-conserving plant that adapts well to the dry air and sunny windowsills of many homes. There are thousands of species of cactus, and selecting a species that does not grow too large or quickly is key to having a low-maintenance houseplant. Providing a gritty, well-draining potting soil in a container with drainage holes, bright light and little but timely watering makes cactus a successful plant for interior enjoyment.
Find a spot in the home for the cactus at a very bright window that receives direct sunlight for several hours each day or one that is very bright with indirect light. Avoid the shady northern window exposure because it's too dim, even in summer.
Use pre-made cactus potting media or mix regular houseplant potting media with sand, perlite and small aggregate stones like gravel or pumice. The soil in which the cactus grows must be coarse and sharply draining. Make sure there is at least one drainage hole on the bottom of the plastic or terracotta pot that is home to the cactus.
Water the cactus sparingly in the fall, winter and spring. Allow the soil to become very dry before adding room temperature water, adding just enough water so that it soaks in and dribbles out the bottom of the container. The soil must never be soggy.
Increase the waterings slightly to be more frequent during the warmth and more intense sun rays of summer. Stop adding water to the soil once you see the water draining out of the container's bottom drainage hole.
Apply granular fertilizer to the cactus container's soil each spring with a low nitrogen formula such as 2-7-7. Cactus grows better with higher quantities of phosphorus and potassium. Do not fertilizer cactus in fall or winter.
Consider re-potting the cactus only after it has become overly large or pot-bound in the container. The slow plant growth will warrant re-potting once every two to five or more years. The less direct sunlight, heat and water it receives, the more slowly a cactus grows in the home.