Terrariums

The idea of a terrarium is relatively new. Only a century has passed since Nathaniel Ward accidentally discovered a few plants growing in a little soil inside a discarded bottle. Ward developed his discovery into the intentional culture of plants in bottles and glass containers, a practice which is now popular all over the world.

The major factors contributing to the popularity of terrariums are more leisure time and a growing awareness and concern for what live plants mean in our environment. Artistically arranged and designed, plant materials create a new dimension to our crowded living space. Now, with an increase in the number of people living in apartments and condominiums, access to natural beauty is becoming increasingly difficult for the average person and more and more people are becoming interested in indoor gardening in miniature. In a small garden under glass one can see and enjoy nature and not be bothered with the difficulties of large scale gardening.

Traditionally, clear glass is used for terrariums. This can be in the form of goldfish bowls, glass covered candy jars, aquariums, gallon, pint or quart jars, canning jars or salad oil bottles. In addition to clear glass, many types of acrylic or clear plastic containers are available which are very satisfactory for terrariums. These are usually less expensive and more durable than glass containers. Depending on the type of terrarium that is to be constructed, these containers may have a lid or stopper to make the system air tight.

The color of the plastic or glass is also important to consider for at least two reasons. First, you have to be able to see inside the terrarium to appreciate it. Second, light has to enter the terrarium if plants are to survive. Colored glass is available and can be very interesting, but the choice should be restricted to those types of glass that have only a very slight tint.

Assemble a terrarium by lining the bottom and about 1/5 of the walls of a clean container with pea-size gravel to provide for excess water. Add a thin layer of charcoal over the drainage materials to absorb unpleasant odors which can occur when terrariums are over watered. The size and shape of the container will determine the amount of drainage material that should be used. A 1/2-inch layer is about the minimum and 1 1/2 inches should be enough for large containers. Place a piece of synthetic fabric over the drainage layer to prevent soil from settling into it and destroying its ability drain. Materials, such as fiberglass draperies, nylon stockings or discarded curtains are good choices because they are porous enough to allow water to pass through, fine enough to hold soil particles, and will not decompose rapidly. Next add enough sterilized soil mix to fill approximately 1/5 of the container, being careful to keep the soil off the walls of the container. Premixed potting soils can be purchased for terrariums. These soils are sterilized and, therefore, do not contain disease organisms which may cause rot or deterioration of the plants. The soil can then be leveled or molded into contours and valleys with a tablespoon, teaspoon or any other blunt instrument.

After the soil has been arranged in the container, rooted plants can be planted. If a bottle-type container is used, it might be necessary to use long tweezers to place the plants and other accessories. Shallow depressions should be made with the tweezers for the plant roots, the roots should then be covered with soil and the soil should be slightly compacted with a blunt instrument. Place accessories such as stones, sand, rocks and driftwood, at the desired location in the terrarium.

Along with enthusiasm and imagination, a little knowledge of plant materials and their growth habits is necessary when building a terrarium. Choose small plants that have a dwarf growth habit or possess a characteristic which makes it possible to dwarf their growth in a terrarium. A tiny sanseviera may be a small plant in a 2-inch pot, but it has no place in a terrarium because it grows so fast. On the other hand, some plants which at first seem unsuitable for terrariums may work out quite well because they limit their growth when they are in a confined space or because they can be dwarfed by judicious pruning. Boxwood, pittosporum and podocarpus are examples of plants which can be kept from getting too large in a terrarium if they are cut back periodically. Peperomia and small vines tend to stay small in a terrarium even though they may grow large elsewhere.

Many failures in terrariums are due to over fertilization. After the initial fertilization at planting, there is no need to add more unless the plants begin to develop a slight yellowish coloration. Apply a water soluble house plant fertilizer at 1/4 of the recommended rate.

Over-watering is the number one problem in terrarium maintenance. Since a terrarium is a closed system, it may need to be watered only once or twice a year. Too much water may cause excessive growth plus possible disease problems. Since the container has no drainage, terrariums should only be watered when the soil is dry to the touch, adding only enough water to moisten the soil. Plants left in standing water will usually succumb to root rot diseases or molds which cause the leaves of the plants to turn yellow and gradually brown.

Periodically the glass will need to be cleaned with a damp cloth to remove dust particles.


Copyright by Dr. Bob's Gardening Tips