The word terrarium means “a place of earth.” This may seem to be a modern concept when in fact, the art of Bonsai, keeping trees small by root cutting, is centuries old. Exotic fish raised in garden pools and indoors was a fine art in ancient China. Terrariums have become more popular as our cities grow larger. These miniature environments satisfy the desire to bring elements of nature inside our homes and workplaces.
The basic idea for terrariums as we know them was developed in 1829 by Dr. Nathaniel Ward.2 Unable to grow delicate bog ferns in his London garden, he successfully grew them in a laboratory jar where they were free of smoke and pollution. He discovered that plants would grow there unattended for years without adding water or air. Only the correct amount of light needed to be determined. Plant collecting became very popular, and collectors sought species from remote places. Most plants did not survive long journeys, succumbing to severe temperatures, lack of light and salt air. In 1832, Dr. Ward filled two glass containers with ferns and grasses and sent them to Australia. After seven months at sea, they arrived intact. Ten years later, Ward published a book telling of his ability to keep plants in a bottle without watering for 18 years. This was a boon to tea and rubber growers who now had a way to ship plants and to extend plantations throughout the globe. Wardian cases were widely accepted in Victorian homes. The idea that man could control nature was popular with people of that era also. In the past 100 years, although light admitting enclosures for living things have taken many forms, all fall under the general heading of terrariums. A Wardian case may be seen in New Haven in the conservatory at Edgerton Garden on Whitney Avenue.
Terrariums, like aquariums, can be seen as a art form. Consider the difference between putting a plant in a pot and creating an ecosystem, a sophisticated, complex natural environment. The latter provides opportunities for pleasure and learning. Regard it as another room because you’ll be using color, shape, space and light, all of which are elements of design.
An overview of the various types of environments in the world which can be created within a terrarium will demonstrate the range for creativity.3 This means making decisions and as you will see, the first decision will help determine the next and so on.
The first decision-climates for terrariums.
Types of environments
1. Tropical Rain Forest Floor
2. Tropical Rain Forest Floor: Halfway up the trees
3. Tropical Rain Forest Floor: The Treetops
4. North Temperate Forest
5. Semi-Desert: Sun
6. Semi-Desert: Shade
7. Bog or Swamp
8. Water and Bank
9. Cool Weather Type
10. Alpine
The second decision—an open or closed terrarium.
An open terrarium allows air to circulate and there is some loss of humidity. The perpetual rain cycle won’t be present here so watering will be necessary. Openings which may be any size, provide access for trimming plants. A closed terrarium is for those climates which require high humidity such as a bog. A sealed terrarium has constant moisture because after the initial watering a natural rain cycle is established. The moisture is trapped and recycled indefinitely. Light is the plants source of energy and the soil provides nutriments. The cycle is complete and well defined. There are no variables. Light must be a constant daytime presence.
The third decision—animals. A vivarium = terrarium + animals.
Animals may best be left for the more experienced terrarium keeper. Responsibility for even the smallest of creatures is a major consideration. The goal here is to keep the environment in balance. Adding animals complicates the system especially if the system is small. If the system functions without needing cleaning, it is a successful partially functioning ecosystem because the plants, animals, light, water and decomposition processes are flourishing.
Elements of a terrarium. 4
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1. Light
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The beginning of all related life processes. Ranges- sun or artificial, full sun to full shade, direct sun to filtered sun. Artificial light may be a good option.
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2. Soil
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The foundation. Commercial mixes are available or mix one part sphagnum peat moss, one part perlite, one part vermiculite. To one quart of mixture add one tbsp. crushed eggshells. Add more sand for cacti and succulents; more loam for moss. 5 Moisture will determine the type of plants that grow. Humidity is important. Cacti need dry, sandy soil and air, bright sun and daytime warmth. Mosses need a moist, cool, low light environment.
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3. Water
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As we found when preparing the aquarium, chlorine and chemicals are present is tap water, let it stand overnight in an open glass container or use bottled water.
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4. Temperature
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Range is 50-85 degrees for most terrarium plants. Plants need day/night cycle and seasonal rest.
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5. Housekeeping
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The ideal terrarium is a complete ecosystem with the ability to attend to all the needs of life it contains.
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6. Fertilizer
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It is possible to grow plants in a terrarium without fertilizer. If necessary, the proper time to use it is when the plant is doing well. A sick plant can’t absorb and use fertilizer.
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7. Containers
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If you want to think of a terrarium as art, any transparent glass that appeals to you will do. Consider the openings. Don’t throw away those leaky aquariums accumulating in the basement. Garages and tag sales are good places to look for inexpensive containers, especially used aquarium tanks. Their size and opening make them ideal for terrarium planting.
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8. Props
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Rocks, wood, roots etc., may be included to add texture to the design of the environment. Be certain they are free of insecticide and disease.
I’ve chosen two ecosystems to develop for comparison; the first, the sunny semi-desert, an open terrarium without animals. Plants will include cacti and succulents. The second, a bog garden in a partially closed terrarium with a snail, newts, African frogs and water dogs.
Setting up a Semi-Desert: Sun Terrarium
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1. Light: Bright sunlight or one 60 watt light for 10 hours per day.
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2. Air: Circulation is very important, this is an open terrarium.
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3. Soil: Sandy, 1 part humus to 10 parts coarse sand. Keep it moist in summer and dry in winter.
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4. Water: Better to underwater than overwater, let soil dry between waterings. No standing water in this environment. Too much water is deadly for these plants. Use the finger method—poke into the soil, if it’s damp don’t add water. Don’t let the soil be dry for too long either.
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5. Temperature: Not too hot.
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6. Housekeeping: None.
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7. Fertilizer: Liquid may be used.
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8. Container: A 10-15 gallon aquarium tank.
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9. Props: Rocks and twigs.
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10. Animals: None.
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11. Plants: The cactus family is huge. Cacti store water in thickened stems. Succulents store it in fleshy leaves. There are many interesting shapes to choose among. Suggested plants include Gasteria, Aloe, Sedum, Astrophytum, Crassula, Adromischus, Lithops and Rebutia senilis. Thorns and coatings of white or bluish powder are natural sunscreens.6
Arrangements
Set the soil mixture about 3” deep toward the back, slightly shallower in front. Plant succulents in the clay pots they are purchased in where soil is 3” or more deep. This way, soil around the pots can be watered and it will be naturally absorbed into the pot and plants.