Question: How do I start new plants from air layers?
Answer: Air layering is another means of asexual (no seeds involved) plant propagation. Because it is relatively time-consuming, it's generally saved for the more difficult-to-root types of plants. Its main difference is that the new plants remain attached to the mother plants until they have formed their new roots, at which point you can cut and pot them.
The layer should be made 6 to 10 inches back from the growing tip. Cut off all leaves for a 3- to 4-inch section, then use a sharp knife to cut a sliver of the external tissue on each side of the stem. That sliver should be about the thickness of a paper match, and you want to leave it attached to the stem as a flap. Wedge a toothpick into it to keep the freshly cut wood separated from the stem. Dust it with rooting hormone powder. Grab a handful of wet sphagnum moss (as you would use to line a wire hanging basket) that you have been soaking for at least one hour. Squeeze the moss until it barely drips, then place it around the stem. Carefully wrap a piece of clear polyethylene plastic around the moss several times, then secure it with electrician's tape to make the layer air-tight. Roots will begin to form within the moss sometime within the first 6 to 8 weeks, at which point you can sever the layer and plant it into good potting soil. Keep it moist and humid until its roots start to grow. Air layering is especially useful with tropical houseplants such as crotons and ficuses.