Maintaining An Orchid Terrarium

 Terrariums
Nov 022008
 

by Susan Taylor
Originally published in BellaOnline

Once you have your terrarium set up for your orchids maintaining happy and healthy plants is easy if you give them all the elements of their environment they need.

Depending upon the type of plants you have chosen for your terrarium, you will need to provide adequate light. It is important when you set it up to choose plants which require like temperatures and light for best growth. In addition, it is good to try to group your plants by their light  requirements throughout the year. Many epiphytes come from equatorial areas which receive equal amounts of light year round with little change from summer to winter. Your lighting requirements are fairly straightforward in this case: 11 to 12 hours of light. If, however, you have plants such as Cattleyas or other light sensitive plants, you will have to follow a spring, summer, fall and winter schedule. In general, spring and fall should require approximately 12-13 hours of light; summer approximately 15-16 hours and winter approximately 10-11 hours.

Air circulation is a critical factor in maintaining a terrarium. If you do not keep the air moving, you run the risk of encouraging pathogens such as molds which will quickly kill your plants. If you have set up your own aquarium, small computer fans will provide enough circulation to keep your plants happy. If you’re lucky enough to have invested in a professional Wardian case or terrarium, then the fans should already be included. You should also have a vent of some sort to allow warmer air to be moved out of the environment and fresh air in.

Temperature is another area which requires control in a terrarium. Artificial lighting causes heat which can quickly rise in the enclosed environment. A  minimum/maximum thermometer which also records humidity is an ideal instrument. You will want to keep the temperature in the 75 degree Fahrenheit, or 24 Centigrade, range for cool growers and 85 degrees Fahrenheit, or 30 Centigrade, for intermediate growers. One great challenge for you will be to lower temperatures enough at night to get the diurnal drop that many orchids need at night. Turning off the lights will provide a relief from the heat they produce, but venting out that heat is the only way to really make a difference. Ideally, you will want a 10 degree Fahrenheit, or 5 Centigrade, drop at night. In reality, this is very difficult to achieve. I’ve even heard of people who put ice cubes in their terrariums at night in order to force this to happen, with mixed results from their efforts.

Growing Orchids In A Terrarium

 Terrariums
Nov 012008
 

by Susan Taylor
Originally published in BellaOnline

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.

 Newer Entries