You'll never hear me claim to know much about orchids. I have a hard time even keeping them alive. I fried a phalaenopsis last year and I have this miniature orchid plant on a wooden board with some moss that might be sprouting a leaf but I'm not sure. It looks pretty fried as well. However - I found a great tip sheet for raising orchids in terrariums or Wardian Cases at the organic-gardeningblog.com. If I had the space for a large terrarium then maybe I could finally raise the orchids of my dreams...
Beyond question, orchids grow best in greenhouses. This fact has barred many people from enjoying this fascinating hobby, since they may have neither the means nor the space for a greenhouse. What can be done then? Some success can be had by placing orchid plants in sunny windows and staging them over trays of moist gravel. Though much success has been claimed for this method, I have found results over a period of two or three years most disappointing both in lack of blooms and in a gradual deterioration of most plants. However, the majority of plants can be placed in sunny windows over gravel trays during their blooming period where they can be enjoyed by neighbors as well.
Without a doubt, greenhouse culture gives best results. Since few can have large greenhouses, the answer is to construct little greenhouses – or Wardian cases (forerunner to the modern terrarium) – which can be placed in suitable windows, facing preferably south or east. The plural is used advisedly because once bitten by the orchid bug, no one is ever satisfied with one Wardian case, provided more than one suitable window is available.
These cases are not expensive if they are homemade. They can be built as simply or as elaborately as individual taste dictates. I have six of different shapes and sizes, all built of windows purchased from a hardware store. The general idea is to make a rectangular box with a hinged door and a hinged top which help to regulate ventilation and humidity.