Location: The genus Bulbophyllum is the largest in the orchid family, Orchidaceae, with over 2,000 species which grow epiphytically and/or lithophytically in nature. These orchids are found in Africa, Madagascar, Central and South America, the West Indies, Southeast Asia, Australia, and various islands in the Indian and Pacific oceans. The montane forests of Papua New Guinea have approximately 600 species and Borneo has over 200.
Light: In regards to foot-candles (fc), a range of 2000-3500 fc is good, which basically translates to bright shade. They like a little more light than Phalaenopsis, but not as much as a Cattleya. Placing Bulbophyllum orchids in a bright eastern window or shaded southern window will provide ample light for plants to grow. Some direct morning sun is fine, but to prevent scorch, don’t expose to midday sun. As always, adjust plants slowly to higher light levels.
Temperature: Due to being the largest genus in Orchidaceae, there is a lot of variation among species. Generally speaking, Bulbophyllum are intermediate to warm growers and prefer 70-80 °F days with a 5-10 °F drop at night. Being that most are spread throughout Southeast Asia, keep in mind the climate existing there. Some species are from more temperate regions and in cooler montane forests so they could grow in daytime temperatures of 60-70 °F with a 5-10 °F drop at night. It is important to provide a certain species’ temperature requirements for optimal plant health, otherwise issues with the plant’s metabolism may lead to its downfall.
Water: A lot of the Bulbophyllum orchids we have are mounted species and absolutely require daily mists. Running tepid water over your mount, or misting with a spray bottle works as well, just get the roots wet and allow leaves to dry by nightfall. Other plants are in small baskets or shallow bulb pans, but they stay moist and may slightly dry between waterings. Do not let these plants dry out completely. However, temperate species may require a short rest so adjust watering accordingly.
Humidity: Being that the genus Bulbophyllum may have originated in the rainforest of Papua New Guinea due to its greatest species diversity there, these orchids need a high humidity of 60% or more, ideally 70-90%. Although this may prove challenging outside of a greenhouse setting, morning mistings are highly recommended, especially during the winter months when homes are heated depleting moisture in the air. Another way to mitigate the effects of low humidity is keeping the plants in a moisture retentive media, such as sphagnum moss. The use of a humidity tray with a dome or cover may also help keep relative humidity high enough for your Bulbophyllum.
Air Circulation: Not only Bulbophyllum, but for all orchids, movement of air is beneficial. The air should be humid to prevent desiccation and the flow should be gentle. Small muffin-type fans are useful for growing areas in the home. Good air circulation tends to result in quicker drying of potting media, which is essential for healthy roots allowing them to breathe.
Fertilizer: A half-strength balanced fertilizer or Michigan State University (MSU) formula solution (reverse osmosis/distilled/rain water or tap water) applied weekly during the active growth months should suffice. For the autumn and winter months, a quarter-strength balanced fertilizer or MSU formula solution can be applied every other week to once a month.
Re-Potting: The less re-potting done for Bulbophyllum orchids, the better. They don’t really like being disturbed as much. Plus, some species of these orchids have long rhizomes and clamber and crawl so growing them in pots may prove to be challenging, but others with shorter rhizomes do well in pots. The media recommended for these plants is sphagnum moss. Mounting and growing in baskets is a preferred method of keeping Bulbophyllum orchids as this allows them to climb and adhere to their plaque or container. The best time to re-pot is at the onset of new growth from which new roots will emerge, allowing better establishment. If the media has broken down, re-pot. If the plants look like they’re starting to grow off their mounts, attach another piece of cork to the existing mount. If the plant has grown off the mount and is robust enough, it may be divided and re-mounted or put into a basket of sphagnum.
Miscellaneous: This genus is to the orchid world, what amphibians and reptiles are to the pet world. They’re an extremely unusual, wild, wonderful, exotic group where people either love them or hate them. From their unique shapes and sizes, colors ranging in everything but blue, to their pungent odors of carrion, or perfumes of fruit, the hobbyist grower will no doubt become intrigued by these plants.