If you have a sunny window, cacti make a great choice for low-a maintenance houseplants. In exchange for a small amount of care, they reward the patient gardener with interesting forms, colors and even spectacular flowers. The secret to growing a healthy cactus is in understanding cactis' specific needs, which are a little different than most other houseplants. By recreating the arid, nutrient-poor conditions of their native desert habitats, you can keep nearly any cactus happy.
Place your cactus in a spot where it will receive the correct amount of light. For most desert species, this will mean full sun. Move cacti that have been growing in the shade into full sun gradually to avoid sunburn. Make sure the cactus remains oriented the same direction, so that the same side will still be facing the strongest sun.
Water your cactus only once a week during the warm months by filling the pot with just enough water to make it drain. Wait a minute or two, and then fill the pot again just until you see water run out if the bottom. In the fall, gradually decrease the frequency of watering to twice a month. In December and January do not water your cactus at all. If the stem of your cactus shrivels noticeably, mist the plant lightly in the early morning hours, with a spray bottle filled with water. Avoid misting plants when they are in sunlight.
Feed your cactus with a liquid low-nitrogen fertilizer diluted to half strength about once a month through the summer, while the cactus is actively growing. Never fertilize newly repotted or winter dormant cacti.
Choose a shallow pot that is wider than it is tall to repot your cactus. Make sure the new pot is just an inch or two larger in diameter than the pot in which the cactus was growing. Repot your cactus in spring or summer, only when it has outgrown its original pot. Wait to re pot your cactus if it has not filled up most of its current pot, if it is in bloom, or temperatures are low.
Fill the pot with one part coarse sand, one part peat based potting soil. Mix this well with your hands. Fold a length of old newspaper into a long, two to three inch wide band, and loop it around the cactus. Gently tip the pot on its side, wearing gloves, and support the cactus with the newspaper band. Pull the old pot away from the root ball, and use the newspaper band to move the cactus to the new pot. Be sure to plant the cactus at the same level it was previously growing in relation to the soil surface.