A decorative idea for growing orchids in the home is the use of a terrarium, conservatory or Wardian Case. The concept behind the use of these items is that you create a mini-greenhouse inside to grow plants. They come in all sizes, colors and shapes to suit almost any décor. It is important to understand what will and will not work for orchids in this type of environment. The major thing to remember is that we are trying to replicate the growing conditions for the orchids we are putting in the chamber. Thus, high humidity, good air circulation and adequate lighting are required.
Terrariums by definition are self-contained ecosystems designed to live without disturbance for a year or more. The water in the container is constantly re-circulated by evaporating and dripping back into the soil or growing medium. Most orchids will not survive well in this kind of an environment because they need more air circulation or they will rot.
A Conservatory or Wardian Case is actually a mini-greenhouse with air vents, perhaps fans, lights, everything necessary to grow indoors. There are any number of combinations that can be used, depending upon your needs. The Orchidarium site has the most complete information I’ve seen, including what accessories are available. If you are considering building your own there are several really good articles available. The Do It Yourself Wardian Case article by Prem Subrahmanyam published in the Tallahassee Orchid Society Newsletter is extremely helpful and detailed.
In corresponding with several people who have successfully grown orchids in enclosed gardens, the primary comments were that it is necessary to have fans going 24/7, keep an opening to allow in fresh air, and to choose orchids which prefer high humidity, have lower light requirements and like the warmer end of the growing spectrum. It is extremely difficult to provide cool temperatures in enclosed spaces while using artificial lighting. One lady even mentioned trying to reduce evening temperatures by putting ice in the bottom of the enclosure, but found that that didn’t work adequately. And, most importantly do not have pots or plants sitting in water!
It is important to have automated controls on a Wardian Case because it doesn’t take much to cause conditions that will kill your plants. In order to keep the humidity up while the lights are on, misters are recommended. It is recommended that lights be used for 12-14 per day. Recommended orchids mentioned were Pleurothallids although Masdevallias don’t seem to like it as much as the Restrepias and mini-Dendrobiums.
One thing that I didn’t hear much about, but I would recommend is that you try mounted plants in a Wardian Case, especially if you are looking for a decorative display. Mounted plants need higher humidity to allow their roots to gather water than those in pots.