Cut a cactus branch at the joint to avoid damaging the mother plant. Use a sharp knife for small plants, or a small saw for larger plants with tough skeletons.
Lay the cutting on newspaper in a warm, dry place for six to 14 days until a callus forms over the cut edge. Let the cutting become dry, but not shriveled. This ensures that the cutting will not rot when planted.
Fill a terracotta pot with cactus potting soil mix. Make sure the pot has drainage holes; dampen the soil very slightly. Mist the soil surface, if possible. Too much moisture will cause mold on the cutting.
Dip the cutting in rooting hormone. Liquid hormone prevents the need to dampen the cutting with water. Bury the bottom 2 inches of the cutting in the soil. Do not water for two weeks, and then water just until the top layer of soil is moistened.