Article 3-5 Hydroponic Orchids

by Cindy Rae

OrchidThere are few things more magnificent than an Orchid. The delicate blooms display nature’s most intricate work in a spectacular array of colours and shapes. The exposed thick white roots and rich texture and shape of the waxed leaves add to the orchid’s appeal. These unique and exotic plants are fascinating to look at and pleasure to cultivate. In the rainforests of South America and other tropical areas, orchids are found growing on the bark of trees or moss covered rocks. The rain runs down the side of the tree or rock supplying the perfect balance of water and oxygen while the roots trap nutrients from decaying vegetation. There is no soil, in essence making orchids “hydroponic by nature!”

Orchid enthusiasts endeavor to simulate Mother Nature’s growing techniques indoors. As in any other type of hydroponic culture, this means an environment must be achieved that meets light, nutrition, humidity and air flow requirements.

A 400 watt metal halide light is ideal for many orchid species. Plants that require intense lighting may be placed directly under the lamp while low light plants grow well in the peripheral. This effectively provides a 6′ x 6′ growing area. The Sunmaster tm Cool Deluxe lamp ensures the blue end of the light spectrum for healthy vegetative growth. To promote lush flowering the lamp may be replaced with a Warm Deluxe bulb to imitate the reds of the harvest end of the spectrum. This method allows the grower to expand the lighting conditions with only one ballast. Once in bloom, orchids may be removed from the grow room and displayed anywhere. Orchids grown under high intensity lights consume more water than those grown outdoors, however it is important to make sure not to over water. The roots should be almost dry before watering.

Orchids grown under supplemental lighting will need to be fed more often because of their vigorous growth. Bernie Huizing, winner of first, second and third prize at the American Orchid Society’s international show held in Edmonton last February, has had tremendous success using hydroponic nutrients for his prize winners. Any white residue build up on the pot and/or roots usually indicates over fertilization. Huizing also suggests using tepid rain water whenever possible during regular watering.

Fresh air and good ventilation are essential for orchids under lights. High humidity required by orchids is an ideal breeding ground for fungus. Good air movement using a wall or ceiling mounted fan will help to eliminate fungus and viruses while circulating the air. To keep humidity to a maximum, walls can be draped with plastic for a greenhouse effect. The benefits are two-fold when white plastic is used; humidity retention and increased light intensity.

Many of the traditional hydroponic growing media work very well for orchids. The inert, sterile media with good air retention make ideal anchors for these plants. Young seedlings can be transplanted into hydroponic growing medium at any time making repotting a simple procedure.

Expanded clay pellets are uniform in size and quite porous allowing plants to easily stabilize while providing great capillary action. Available in a variety of sizes, clay pellets are a great environment for orchids with thick roots and doesn’t breakdown so it can be reused for years.

Perlite and Vermiculite are heated natural minerals which can be used individually or with a mixture of peat and bark as a soilless mix. Both perlite and vermiculite have a light and fluffy quality that won’t get waterlogged. These media are well suited for orchids with thin, airy roots.

Rockwool is a spun rock fiber, available in cubes, slabs and granulated form. Rockwool has enormous water retention capacity while permitting plenty of air to reach the roots.

A mixture of various growing media can be tailored to suit individual orchid requirements. Experiment with one or two plants at a time as you may find that changing the medium may also alter other aspects of the plant’s care.

Multi plant hydroponic systems are not encouraged for orchid growers. The risk of transmitting disease and bacteria through recirculating water is too great. Individual two-part hydro culture pots work best. These consist of an decorative outer shell and an insert with holes that excellent drainage. A water level indicator lets you know when it’s time for watering making it virtually impossible to over water.

Whether you are a serious orchidophile or growing a few varieties to marvel at and enjoy, orchids will enrich your appreciation for Mother Nature’s artistic talents.