Succulents like cacti can be propagated from seeds as well as from cuttings. Many gardeners prefer to use cactus cuttings as it is easier and quicker to get large cacti in this manner. Columnar, segmented or pad-forming cacti are the types that are commonly propagated by cactus cuttings.
To begin with, the cuttings are carefully cut off from the selected succulent. It is advisable to wear gloves while doing this, and to use a sharp knife to make a clean cut. It is also necessary, especially when taking long cuttings, to keep in mind which is the bottom end and which is the top end; cactus cuttings that inadvertently get planted upside down will not grow.
The cut ends of the cactus cuttings are dipped in sulfur to protect them from bacterial infection. The cuttings should then be left in sunny, dry area for a week or two until the cut areas have sealed over and developed calluses. It is important not to plant a cactus cutting until the calluses have developed; they minimize rot as well as bacterial and fungal infections.
The cactus cuttings should then be planted to a depth of 1 or 2 inches (2.5 to 5 cm) in a well-drained soil, and placed in an area of full sunlight. The soil should be moistened a little prior to planting, but the cuttings should not be watered for at least two weeks. After that period, water moderately and again leave off watering for two more weeks. As the cuttings do not yet have any roots, they do not require much water and over-watering will cause them to rot. In addition, cacti are originally the denizens of arid environments and basically have low water requirements.
The cactus cuttings will begin to form roots in about two to six weeks. This can be ascertained by tugging slightly at a cutting; if there is resistance, the roots have developed. Another indication of root formation is that the growing cactus will start to look more firm and green, and will start to develop new growth.
The newly developed cactus plant can now be grown as a regular succulent. This means it will require plenty of sunlight and moderate watering. If you live in a cold climate area, it is important to not water the cactus in winter. Cacti retain water and, at very cold temperatures, this retained water is liable to freeze and thereby damage or kill the plant.