Orchids are a diverse family of plants, and their propagation requires specialized techniques due to their unique growth habits and distinct seed biology. Unlike most plants whose seeds contain a stored food supply, orchid seeds are tiny and lack an endosperm, meaning they cannot germinate without external support. This biological difference necessitates methods ranging from simple physical separation by home growers to complex, sterile laboratory procedures for the continuation of species and the mass production of hybrids.
Dividing Clumped Orchids
The most straightforward method of propagation for many home growers involves dividing a mature plant, a technique primarily used for sympodial orchids like Cattleya, Cymbidium, and Oncidium. These orchids grow horizontally, producing a connected chain of storage organs called pseudobulbs along a creeping rhizome. The process involves physically separating this main root mass to create two or more independent plants.
A division is considered viable only if it contains a minimum of three or four pseudobulbs to support the new growth. These storage organs contain the energy and moisture reserves necessary to sustain the newly separated plant until it establishes a new root system. Separating the plant is best performed during repotting when the rhizome is visible, ensuring the division has enough stored energy to produce vigorous new growth and flower again.
Cutting the rhizome must be done with a sterilized tool, ensuring each new section retains sufficient pseudobulbs and at least one viable “eye,” a dormant bud capable of producing a new shoot. While smaller divisions may survive, they often take longer to regain vigor and may not flower for several seasons. Larger divisions increase the likelihood of a strong, healthy plant that will quickly resume blooming.
Harvesting Specialized Offshoots
Some orchids propagate themselves naturally by producing specialized offshoots that can be removed and grown as new, genetically identical plants. This method of vegetative reproduction is common in monopodial orchids, such as Phalaenopsis and Vanda, which grow vertically from a single stem. The most recognized of these growths is the keiki, a Hawaiian word meaning “baby” or “child.”
Keikis are small plantlets that develop from dormant nodes on the flower spike of Phalaenopsis or along the canes of Dendrobium orchids. They are structurally complete miniature versions of the parent plant, eventually developing their own leaves and roots. A keiki should be left attached to the mother plant until its own roots are at least two to three inches long and it has produced multiple leaves, ensuring it has the resources to survive independently.
Another technique involves the use of back bulbs or canes, which are older, leafless pseudobulbs from sympodial orchids that can still be induced to sprout new growth. These dormant bulbs are removed from the main plant and placed on a moist medium, often in high humidity, to encourage a new shoot to emerge from a latent bud. This practice is particularly useful for increasing valuable clones of orchids like Cymbidium or Catasetum without disturbing the actively growing portion of the mother plant.
Growing Orchids from Seed in a Sterile Environment
Sexual reproduction in orchids, which is the only way to create new hybrids, presents a unique challenge because their seeds lack the necessary food reserves to germinate on their own. Because they lack endosperm, orchid seeds cannot simply be sown in soil. In nature, germination relies entirely on a symbiotic relationship with specific mycorrhizal fungi, which penetrate the seed and supply the necessary carbohydrates and nutrients.
To bypass this unpredictable natural requirement, commercial and hobby growers use a laboratory technique called asymbiotic culture, or “flasking.” This process involves sowing the dust-like seeds in a sterile glass container onto a nutrient-rich agar medium. This specialized medium, which includes mineral salts, vitamins, and sucrose, acts as a substitute for the naturally supplied nutrients from the fungus.
The sterile conditions are mandatory to prevent contamination by bacteria or mold, which would quickly overwhelm the delicate, nutrient-dependent seeds. Once sown, the seeds swell and develop into a tiny, undifferentiated mass of cells called a protocorm. The protocorm then develops a shoot and root, eventually growing into a plantlet ready to be removed from the flask, a process known as deflasking, after several months to a year.
Cloning Orchids Through Laboratory Culture
For mass production and the preservation of desirable genetic traits, orchids are propagated asexually using meristem culture or tissue culture. This technique allows for the rapid multiplication of a single plant into thousands of genetically identical copies, often referred to as mericlones. It is the most efficient way to scale up production of a prized hybrid or a rare species.
The process begins by excising a tiny piece of actively dividing tissue, known as the apical meristem, from a young shoot tip of the parent plant. This explant is placed in vitro on a sterile, liquid or solidified nutrient medium precisely formulated with plant growth regulators, such as auxins and cytokinins. The meristem tissue proliferates, forming small, undifferentiated masses that resemble the protocorm stage of a seedling.
These protocorm-like bodies are repeatedly divided and subcultured onto fresh media, resulting in geometric multiplication. This allows commercial laboratories to produce millions of clones from a single parent plant, ensuring that every resulting orchid is a perfect replica with identical flower color, shape, and size. Meristem culture is the primary reason that high-quality, complex orchid hybrids are widely and affordably available today.