Terrariums are small, indoor gardens that can be constructed to be either enclosed or open. Orchids, with their bright, beautiful flowers, can be a welcome addition to a tropical terrarium, but it is important to remember that not all orchids are created equal. Smaller orchids will generally fit into a terrarium better than larger varieties, and with the high humidity of enclosed cases, it's important to find a plant that can adapt.
Jewel orchids are grown more for their foliage than for their flowers, which tend to be small and nondescript. The leaves of jewel orchids have intricate patterns, and many varieties have a metallic sheen to them. These tropical plants thrive in warm, humid climates; because they need such a high humidity, they are difficult to grow indoors outside of an enclosed terrarium. Most remain fairly small, also making them suitable for a terrarium. There are a number of species within the family; the Ludisia discolour is a small plant with metallic veins that has small flowers, while the Macodes petola has oval leaves that look like they have been sewn with golden thread. The "Black Velvet" cultivar of the Ludisia discolour is an eye-catching orchid named for its black leaves.
The Phalaenopsis family of orchids is a long-blooming variety of orchid that thrives in temperatures between 75 and 85 Fahrenheit. Because most orchid terrariums are enclosed, it is important to select a variety that does not have a requirement of much air movement. As long as the humidity is kept between 50 and 60 per cent, the Phalaenopsis does not require the placement of fans to keep air circulating. This orchid can bloom for up to 8 months a year, producing colourful flowers on spikes. They also do well in partial shade, allowing them to be planted comfortably with taller plants that can potentially block sunlight.
Lady Slipper Orchids
The lady slipper orchids best suited for terrariums are from the Phragmipediums family. This group originated in South America and Mexico, and is more tolerant of conditions in which the humidity is between 50 and 60 per cent. High humidity can cause orchids to rot, making air circulation crucial; varieties like the caudatum types of orchids require less humidity and are therefore less susceptible to developing rot problems. These orchids get their name from their distinctive shape, which resembles the dainty slipper of a lady. They come in a variety of colours, and can also tolerate cooler temperatures than most orchids -- between 50 and 60 Fahrenheit. CTaudatum lady slippers have long, slender leaves and require the most sunlight of all the lady slippers.
Angraecum orchids are a group of plants native to Africa and Madagascar. Some of the miniature varieties are well suited to terrarium life. Most of these orchids have a distinctive star shape and deep green leaves. One example of a suitable angraecum is the "Lion's Moustache" orchid. This small variety, which usually reaches no more than 8 inches tall, does not require soil to grow, and can grow quite well on coconut fibres or wood shavings. Thriving in hot temperatures and high humidity, the orchid bears white flowers less than 2 inches in diameter.