The plants that are the most cost effective to grow and sell indoors are many of the same plants that are readily available in nurseries and garden centers. The key to cost effective growing is the ability to create many new plants from a single parent. Harvesting and planting seeds works, but the offspring plants will not be identical to the parents. Asexual reproduction — creation of clones — is necessary to produce a consistent crop. This can be done by several simple methods.
Rex begonias (Begonia rex-cultorum), hardy in U.S. Department of Agriculture plant hardiness zones 10 through 11 and grown indoors elsewhere are very cost effective to propagate indoors. Grown for their colorful, sometimes ruffled, leaves, large numbers of rex begonias can be propagated cheaply by detaching individual leaves, pinning them to the surface of pots of damp vermiculite, and making small slits in the leaf veins. If the vermiculite is kept moist and the pots are kept covered, new plants will grow from the incisions. This technique also works on angel wing begonias (Begonia coccinea), hardy in USDA zone 13.
Swords and Violets
African violets (Saintpaulia spp.), hardy in USDA zones 11 through 12 and mother-in-law’s tongue (Sansevieria trifasciata), hardy in USDA zones 10 through 12, are indoor plants that can be propagated in large numbers without special equipment or conditions. African violets are grown for their vibrant flowers in shades ranging from white, yellow and pink, through a range of purples. Mother-in-law’s tongue is a foliage plant, known for its erect, sword-shaped leaves. To propagate either plant, insert cut leaves in pots of moist vermiculite and enclose the pots in plastic bags. Rooting will take place in several weeks.
Spiders and Offshoots
Some indoor plants produce large quantities of offspring by sprouting long stems or runners. The new plantlets that form at the ends of the runners can rooted and grown on to marketable size under normal indoor conditions. Species that produce plantlets include spider plant (Chlorophytum comosum), hardy in USDA zones 9 through 11 and strawberry begonia (Saxifraga stolonifera), hardy in USDA zones 6 through 9. To root the plantlets, fill small pots with moist vermiculite. Pin plantlets to the vermiculite with hairpins, taking care not to detach them from the runners. Watch for signs of new growth before detaching.
Indoor Growing Considerations
When propagating and growing plants indoors for eventual sale, make sure to use vermiculite rather than potting soil. Vermiculite is sterile, which helps prevent the young plants from rotting. Allow enough space between leaves or cuttings for good air circulation. Place propagation trays or pots in draft-free locations where they will receive indirect light. Keep the vermiculite moist, but not wet. When rooted leaves, cuttings or offspring plants have developed new growth, transfer them to small individual pots and grow them to salable size.