How to Grow Indoor Cactuses

Place your plants in an area where they will receive full sun, such as a south-facing window, unless you have a cactus that prefers shade -- some do. Make sure the area is insulated from cold, so a wintry draft will not harm the plants. If you lack natural light, place the plants under a fluorescent plant light and leave the light on 14 to 16 hours per day.

Water the plant when the soil becomes dry and crumbly to the touch. During the growth season -- from spring to fall -- the plants need regular watering. At this time, water until liquid flows from the drainage holes in the plant containers, emptying out excess liquid from the saucers or watering over a sink. In the winter, water cacti and succulents only enough so the plant tissue does not shrivel. Slowly increase watering when the plant begins to grow again.

Move plants outdoors for the late spring and summer if desired. This benefits the plants, spurring growth because of the increase in natural light and warmth. If you don't have access to outdoor space, the plants will be fine indoors. Bring outdoor plants back inside in autumn, when temperatures reach 40 degrees Fahrenheit.

Fertilize cacti with a houseplant fertilizer diluted to half strength one to two times during the growing season.

Watch for plant pests, such as mealy bugs. Evidence of pests include holes in the plant tissue, visual evidence of plant pest or other problems. Treat pests with an insecticidal soap or other treatment intended for cacti and succulents. Some plants are sensitive to certain formulas, so test a formula on part of the plant before applying it to the whole. If the plant appears damaged, try another insecticide.