Cactus is a large family of plants, all the members of which are also succulents. Cacti are perennials, with several thousand species from which to choose. There are varieties that prefer sun and some that, surprisingly, prefer shady conditions.
The plants require little maintenance or care, so it is more important to give proper care during the times they do need intervention. Cacti can tolerate a lot of abuse, but to attain their best condition and experience the fewest problems, there are a few rules that must be followed.
Choose containers according to the size of your cactus plants. Taller selections need to be in a pot that is as wide as half the height of the plant. Round form cacti require about 2 inches more pot than the width of the plant. Similar spacing can be used to place multiple cacti in the same pot.
Select clay pots to help the soil to dry. Their weight also helps keep larger specimens upright. Clay pots can lead to a condition where salts accumulate on the inner sides of the container, encouraging roots to cling to the pot. Choosing glazed pots instead can address this condition.
Mix your own sandy soil by adding horticultural sand to potting mix, peat or compost (special potting mixes are sold specifically for cactus). Cacti need coarse and porous soils with small amounts of organic matter. A cactus can tolerate loam or sandy soil, acidic or mildly alkaline conditions. Soil should drain well.
Allow the roots time to heal over any areas damaged during planting before you water them. The horticulture department at Texas A&M University suggests planting in a dry pot, with dry soil and waiting to water for several days in order to prevent rot.
Locate your container in a southern-facing window to take advantage of the light and heat produced by the sun. Still, most cacti are hardy enough to survive freezing temperatures and cooler temperatures might be required to force blooms.
Avoid overfeeding cacti as this can lead to disease. Excess organic matter in the soil can trap moisture, which leads to rot. Overfeeding also creates an unwillingness for the plant to produce flowers.
Cacti require more phosphorous than nitrogen and should be fed during their time of growth, generally in spring and summer. Feed less than once per month during other periods.
Water every three days during spring and summer and reduce watering to every five to eight days during the fall and winter. Moisten the first 2 inches of soil and allow any extra water to drain off.