House Plants: Terrariums

Terrariums are miniature gardens enclosed in glass or clear plastic. Any type of house plant can be grown in a terrarium arrangement: indeed, the humid microclimate inside the container is the ideal solution to dry, centrally-heated rooms which can be harmful to plant health. The one exception to this is the family of cacti and succulents, prone to rot in humid environments. These are better kept in open dishes.

Terrariums require a minimum of care if they are kept sealed. The moisture that plants absorb from the soil is given off through the leaves by the process of transpiration. This condenses on the glass walls and runs down to moisten the soil again. The atmosphere also remains balanced through the combined plant processes of photosynthesis and respiration. A well-constructed terrarium requires only light and warmth to flourish.

Container

Any clear or tinted glass or plastic container can be used if it will admit light and allow plants to be seen. Fish tanks, brandy snifters, pickle jars and casserole dishes all make attractive displays. If they do not come equipped with a lid, a sheet of clear plastic or glass makes a suitable cover. Small openings in the top of the container are acceptable, but you may need to add water from time to time. The container must be clean, bacteria; fungi and algae thrive on soiled surfaces in warm, moist environments.

Choice of plants

Most plants recommended for terrariums and bottle gardens are moisture-loving types which never become large. Because most house plants are of tropical or subtropical origin, they thrive in the terrarium environment. Apart from cacti and succulents, the selection is nearly unlimited.

Choose plants with similar requirements for temperature, light and water. For example, mosses and ferns which thrive in poorly-lit areas are incompatible with coleus or crotons which need strong light to remain healthy.

Miniature flowering plants fit particularly well into terrarium arrangements, including miniature African violets, roses and geraniums. For a woodland effect, mosses, lichens and small ferns can be gathered from a nearby forest and planted. Small stones, pine cones or bits of wood create a natural effect. Grass seed sprouts easily to make an attractive groundcover.

Desertariums

Desertariums are enclosed gardens for plants requiring very dry conditions. Desertariums should be planted in wide, uncovered containers to allow moisture to escape and air to circulate. Use a sandy soil with at least a one inch layer of drainage material in the bottom. Be careful not to keep the soil too moist. Plants to use are cacti, aloe, agave, crassula, sedum, sanseveria, echeveria, haworthia, kalanchoe, opuntia and cotyledon.

Planting

Wide-necked terrariums are easy to plant. Some people prefer to line the bottom first with sphagnum or freshly-picked moss, up to the soil level. A drainage layer is essential to ensure the roots are not sitting in excess moisture. Spread a handful of crushed charcoal in the bottom to keep the soil fresh, and cover with 2 cm pebbles or gravel. Cover this with 2 to 5 cm of good, porous potting soil. Mosses and ferns prefer a humus soil. A mixture of one part organic matter, one part loam and one part coarse sand will satisfy most plants. The soil mix should be slightly damp, but never wet, at the time of planting. It must be sterile.

You may wish to create a landscape effect by making `hills and valleys' with the soil.

Dig small holes in the soil and place the plants in them, firming the soil gently around the roots. Make sure that no plants are touching the sides of the container, their leaves would turn brown.

Planting a bottle garden is not as difficult as it may first appear. Special tools are easily constructed from household items.

You'll need: A funnel (plastic or improvised), blunt ended stick, pointed stick, sundae spoon, sharp scissors, kitchen tongs, spring-operated pick-up device and coat hanger.

• With a funnel, pour in the drainage material (pebbles or gravel, and a small amount of crushed charcoal to absorb odor). If a long-necked, wide funnel is not available use the cardboard from a paper towel roll or a rolled-up piece of heavy paper.
• Pour the soil layer in through the funnel and firm and level it with a blunt-ended stick.
• To dig a hole for the roots, in the soil use a pointed stick or a sundae spoon.
• Trim excess foliage if necessary with sharp scissors. Wrap trailing roots into a loose ball to make them easier to handle inside the bottle.
• Grasp the plants at the roots with a pair of kitchen tongs, or unbend a coat hanger and shape the hook so that it will hold the plant. (Make sure beforehand that the wire can be easily disengaged once the plant is inside the bottle). A convenient tool available at hardware stores is a spring-operated pick-up device, long-handled with a small metal claw at the end.
• Bend the leaves up, and lower the plant carefully into the bottle. Lay it on its side with the roots over the hole you have dug.
• Remove the pick-up tool and using the blunt stick, firm the soil around the roots and straighten the plant.
• When all the plants are in, add water gradually, letting it trickle down the side of the bottle until the soil is evenly moist. Avoid overwatering; only a small amount of water is needed.
• If the glass has become dirty, wrap a piece of cotton around the coat hanger and wipe clean. When arranging the plants, keep two factors in mind: size and contrast. If the garden is to be viewed from one side only, place the larger plants in the back to avoid obstructing the view of the smaller plants. If it is to be seen from all sides, larger plants should be placed near the center, surrounded by the smaller varieties. The most attractive displays use contrast as the major guidelines in arranging plants; contrast in leaf color, texture, size, shape and variegation patterns.

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