Compared to other types of plants, orchids can be some of the easiest to propagate from a cutting. The important thing is to understand where to cut the orchid, which depends heavily on what type of orchid you have. Generally, orchids fall into one of two categories: epiphytic orchids (or tree-dwelling), and terrestrial orchids, which grow in the ground.
Take your cutting. Epiphytic orchids usually send out aerial roots from one or more points on the stem. Cut the stem just below these roots.
Plant the cutting. Place a small amount of orchid bark in a planting container that has plenty of drainage. Hold the orchid in place with the roots resting on top of the bark and gently fill in additional bark to cover the roots and hold the plant in place.
Water thoroughly. Ephiphytic orchids need frequent watering to keep the bark moist, but should never be left sitting in a pool of water.
Terrestrial (Ground-Dwellers) - Sterilize your tools. Before cutting any orchid, be sure your pruning shears are clean and free of any bacteria or chemicals that could infect and harm your new plant.
Take your cutting. Terrestrial orchids should be cut at the base of the plant, so that the cutting includes at least one pseudobulb (the swollen, fleshy portion at the base of the stem) and a few roots. It may be necessary to temporarily remove the whole orchid from its container.
Plant the cutting. Place a small amount of soil-based planting medium in a small container with adequate drainage. Hold the cutting in place with the roots resting on top of the soil while filling in enough additional soil to cover the roots. Do NOT bury the pseudobulb.
Water your new plant. Drench the soil well and allow the pot to drain thoroughly. Keep the soil damp but never soggy.