Orchids are categorised into two types, the monopodial and the sympodial. The monopodial has a single upright stem growth habit while the sympodial produces new shoots (or known as keiki) sideways. In both types they develop adventitious aerial roots. When pollinated, the flowers develop capsules containing microscopic seeds. Seed dispersal involves the bursting of the dried pods and seeds being spread by wind. However, seed germination is very low in a natural environment because it requires the aid of mycorrhizal fungi for germination. Difficulties in seed germination are however, replaced with success in vegetative propagation.
Once the pseudobulb of sympodial orchid has finished flowering they will produce keiki sideways. A pseudobulb that has produced flower will never develop floral structure, and the general practice is to remove them. However, leaving the old pseudobulbs has its advantages; the leaves continue with photosynthesis and produce food supply for the keiki and the pseudobulbs continue to store food. Besides, orchids foliage has its own beauty as house plants. Monopodial orchids can be propagated through stem cuttings. Each cutting can be about a foot long with leaves and at least 3 strong aerial roots. Some orchids are terrestrial, but most orchids are epiphytes.
Naturally, they develop robust aerial roots to grasp on treetops. The roots are covered with a thin layer of white cells, to protect the roots as they are exposed and to reduce water loss. They absorb water and nutrients from the green tip of the roots. In a sense, they don’t really require planting media. In fact, cuttings of monopodial (especially Vanda and Arachnis) can be suspended in the air providing they are given regular misting. A good tip is to let Spanish Moss (Tillandsia usneoides) grow with the dangling roots as this will help to trap more moisture and nutrients. Nevertheless, a good potting mixture for orchids would provide the roots surface area to cling on, ample moisture, optimum temperature, and good aeration.
Phalaenopsis keiki on a flower stalk
Planting and maintenance tips:
Orchids can be sold in ceramic pots, glass jar or in the simplest form or a plastic orchid pot. They come in planting media made of wood chips or wood bark. Sometimes they do come in pots of compost. Although Phalaenopsis grows better in small, confined pots, transfer them into clay, ceramic pots or glass vessels. For glass jars or vases, place some Leca beads at the bottom, followed by loosely place wood chips/bark. Keep the water level just above the surface of the Leca beads. Another form of good planting media for orchids are a mixture of broken clay and charcoal at a ratio of 1:1. The clay provides the surface for the roots to grasp and the charcoal can retain moisture. Roots do not have to be buried deep and they can survive out of the planting media. Once the Phalaenopsis has finished flowering, cut the flowering stalk but leave 1-2 nodes behind as this will encourage more development of new inflorescent produce, or leave the flower stalk as it is and do not cut this (especially with miniature Phalaenopsis) and a new inflorescence will arise from the old ones or, keiki can be from the flower stalk.
Indoor monopodial orchids have the best growing habits when they are place on the windowsill facing the early morning sun and away from the internal heating. Feed them once a week with any chosen orchid feed. Keep the sympodial from direct sunlight. An ideal place would be the bathroom as moisture are high. Keiki from monopodial can be separated and transferred to a new pot when they have three or more leaves, or generally when they are 5 cm tall.
In conclusion, orchids are easy to maintain and require minimal attention. Provide them with the ideal condition and they will continue to flower.
By Dr. Nur Abdullah