Stem Cuttings and Leaf Cuttings
An easy method of propagating houseplants is with stem cuttings. In this method, healthy 3 to 4 inch tips are cut from the mother plant, dipped in a rooting hormone, and thrust about an inch into damp perlite or individual expanding peat pots. A plastic humidity tent or a fog sprayer is used to conserve moisture and hasten rooting. Cuttings should be kept in a light, but not sunny, window and transplanted in small pots when roots have developed enough to resist a gentle tug. The potted plants should be covered with plastic bags or fog-sprayed frequently and gradually may be moved into full light. Plants can also be raised from leaf cuttings, using the same steps as for stem cuttings.
The best method of propagating a large accent plant, while pruning it back, is air layering. In this method, a ball of damp sphagnum moss is wrapped about a stalk or branch at the point where the new root system is to be grown and is enclosed in a sheet of plastic securely tied to the stalk. In the case of woody plants, a collar of bark is shaved off and the branch rubbed with rooting hormone. When a good root system is visible through the plastic, the new plant is cut off and potted.
Division of Rootstocks and Runners
Plants with rootstocks that develop multiple crowns, such as snake plant, are propagated simply by unpotting the plant, gently disengaging the roots of younger plants and potting them. Runners are easily propagated by holding young plants in place in a new pot of soil until they take hold and then cutting the runner loose.
Raising plants from seeds is usually done to get a head start, as with garden annuals.
However, plants not available pot-grown are also raised from seeds by the indoor gardener. Seeds are best started in a sterile mediun such as perlite or vermiculite, which are not subject to the damping-off fungi. Generally, seeds should be planted in a flat or shallow pot, at a depth of half the seed's diameter (tiny seeds should be simply pressed into the planting mixture with a flat piece of wood) and watered with a fine spray. As soon as the seeds sprout, good light is needed, or the seedlings will quickly grow spindly. A reflector on the room side of the plants helps to keep them from leaning toward the light. After the first true leaves form, the seedlings are ready to be transplanted.