Dendrobium bigibbum orchids, also known as Cooktown orchids, are a suitable choice for beginners or those who don’t have a lot of time to spend caring for their plants. Placed in the right location with the right natural humidity or on a pebble tray, they are low-maintenance compared to many other types of orchids, and can survive some neglect, since they tolerate drought well.
Mature Dendrobium bigibbum orchids can be damaged by overwatering. When the soil is dry to the touch, it is time to water. Young, growing plants, on the other hand, should be kept moist during their rapid growth phase. Water the orchid when the soil is still slightly damp. Dendrobium orchids that are in bloom should be watered the same way as mature plants, allowing the soil to dry between waterings.
As tropical plants, Dendrobium bigibbum orchids require high humidity levels. Humidity should be kept between 50 and 60 percent. Orchids can be misted daily with water from a spray bottle, but the nature humidity of the environment or pebble trays generally can provide the continuous moisture that plants prefer. Simply place the orchid on the pebble tray and make sure the tray is always filled with water. A hygrometer measures humidity and allow you to tell whether your orchids are getting the moisture they need. Hygrometers can be purchased at nurseries and home improvement stores.
Dendrobium orchids love light and are healthiest when given plenty of indirect sunlight. They can be grown under fluorescent lights, but need to be placed directly under the lights. Dendrobiums are temperature-sensitive; they tolerate heat well, but not cold. To bloom, they require at least a 10-degree difference between day and nighttime temperatures. These orchids will thrive and bloom best when daytime temperatures are between 80 and 90 degrees Fahrenheit and nighttime temperatures are 60 to 65 degrees.
Apply diluted 20-20-20 fertilizer once a week. Mix the fertilizer at about one-quarter of the strength recommended by the manufacturer unless the fertilizer is made specifically for Dendrobium orchids.
In nature, Dendrobium bigibbum orchids grow on trees, not in soil. Because of this, they require a light, loose medium that provides plenty of air circulation. Bark chips work well, as do coconut husk, perlite or a mixture of these mediums and small stones.
Unlike many species of orchids, Dendrobium do not require frequent repotting. They should be repotted only once every two or three years. They prefer small pots, and should not be given too much room. When repotting, use a pot that is only slightly larger than the previous pot.