Dendrobium (Dendrobium spp.) is a vast and diverse genus of flowering plants comprised of more than 1,000 species of orchid. Although they can be grown outdoors in U.S. Department of Agriculture plant hardiness zones 9 through 12, they are most frequently grown indoors as houseplants. The flowers of these orchids can be a mix of several colors or solid orange, yellow, purple, pink, brown, green and white. At an average height of 8 inches, miniature dendrobiums are much smaller than other dendrobium species but also much less likely to be top heavy or require staking.
Place the dendrobium where it will receive large amounts of indirect sunlight. A lightly shaded south-facing window is ideal. Maintain daytime temperatures between 65 and 75 degrees Fahrenheit and nighttime temperatures between 55 and 60 degrees Fahrenheit.
Maintain a humidity level of 50 percent around the orchid. Increase the humidity level around your dendrobium by placing the plant on a shallow tray filled with gravel or pebbles and water. Ensure the bottom of the plant’s container is sitting on top of the rocks and not down in the water. Frequent misting with a spray bottle will also increase humidity.
Water your dendrobium twice a week in the morning with warm water, allowing the potting medium to dry out almost completely between waterings. Do not use distilled water or salt-softened water to irrigate the plant. Always check the potting medium to make sure it is dry before you water – too much water is a much more common problem with orchids than underwatering.
Fertilize with a 20-20-20 or other balanced liquid fertilizer once a week at one-quarter strength.
Run warm water through the orchid's pot for several minutes to flush any salt or mineral buildup out of the growing medium. Perform this cleanse once a month.
Prune your orchid when the blossom stalk begins to turn yellow or brown, cutting the spent stalk 1 inch above the place where it originates on the plant. Always use a disposable razor blade or clean pruning shears to prevent spreading disease from one plant to another.
Repot the orchid every two to three years in the winter or the spring after the plant blooms. Put the plant in a small new pot filled with a potting mix that is one part medium fir bark, one part large fir bark, one part red lava rock or large pumice, and one-half part charcoal. Lightly water the newly repotted orchid immediately after replanting and leave it alone for one week before resuming your normal watering schedule.
Reduce the amount of fertilizer deciduous dendrobiums receive in the fall and stop fertilizing altogether when growth stops. Watering may also need to be reduced during dormancy, so always make sure the soil is dry before watering. Resume your usual fertilization and watering practices in the spring when growth resumes. Evergreen dendrobiums may not require any seasonal care changes.