Terrariums - Miniature Gardens Under Glass
By Bob Chapman
When the memories of the summer garden have faded and the skies often cloudy, many gardeners revert to the indoor mode of gardening. While potted houseplants offer some taste of the outdoors, they often do not fill the need many have for looking at a cluster of living plants. Enter the terrarium. Filled with plants of many shapes, sizes and colors, a terrarium offers a small, but powerful vista reminiscent of the outdoors.
These miniature landscapes under glass have few pest or disease problems. They are easy to maintain. Terrariums have controlled temperatures and atmosphere. Correctly planted, and after the initial watering, they seldom need attention. You will be able to admire your miniature landscape for a very long time.
A plant root extracts moisture from the soil and transports it to the leaves. Some is used in the manufacture of food; the rest is released thru the pores of the leaf. An enclosed terrarium traps most of the moisture and it condenses on the glass and it is returned to the soil, completing the cycle. This “rain” allows the terrarium to go for weeks without watering. All that terrariums need is warmth, a source of light, nutrients and some replenishment of lost moisture to grow and live for many years.
A terrarium is nothing more than a collection of compatible plants growing in an enclosed, or partially enclosed, clear container. There is a wide choice of containers to choose from. Many use the ready-made terrariums available on the market. Others prefer bottles, aquariums, fishbowls, jars or the ever-popular brandy snifter. Any container that meets the criteria can be used for a successful terrarium. One thing to keep in mind is that the terrarium must have a cover. The cover (glass, clear plastic or Saran wrap) holds the moisture inside and helps maintain the temperature. Always wash the container in hot soapy water and rinse thoroughly before using.
Your terrarium needs soil, drainage and something to keep the air clean and clear.
1) The bottom layer consists of pea gravel, pebbles or very coarse sand. This layer is needed to keep the soil doesn’t become over-saturated leading to possible root rots. Spread at least an inch of drainage material over the bottom (larger or deeper containers may need up to three inches of drainage material).
2) Over this layer of drainage material spread a thin layer of activated charcoal to help clean the air of fumes caused by decomposing organic matter.
3) Spread a thin layer of sphagnum moss over the charcoal. This layer will prevent soil from sifting into the drainage materials.
4) The soil is now added. Use OSH Potting Soil. It has the right mixture for making plants grow.
Generally, the smaller-growing houseplants are the ones used for terrariums, but there are wide variances in plants used by advanced terrarium builders. The light requirements and the size of the plants determine those to use. Here are a few selected plants to consider. Select them for their size, leaf shape and coloration. There are many not on this list that are suitable for growing in terrariums. You’ll have fun selecting plants and watching them grow.
Ground covers. These crawlers can make your terrarium look like a woodsy scene. They will cover the bare soil in a terrarium.
-- Irish moss (Selaginella sp.)
-- Maidenhead spleenwort (Asplenium trichomanes)
-- Baby Tears (Helxine soleirolii)
Low growing plants. These are considered foreground plants, growing to about 3” tall.
-- Swedish Ivy (Plectranthus australis)
-- Miniature Peperomia (Pilea depressa)
-- Wintergreen (Gaultheria procumbens)
-- Button Fern (Pellaea rotundifolia)
-- Oxalis (Oxalis sp.)
-- Venus Flytrap (Dionaea musciula)
-- Sundew (Drosera spp.)
Medium height plants. These will grow anywhere from 3-12 inches tall.
-- Bloodleaf Iresine (Iresine herbstii)
-- Bird Nest Sanseviera (Sanseviera trifuscata)
-- Tahitian Bridal Veil (Gibasis geniculata)
-- Nerve Plant (Fittonia elegans)
-- Spider Plant (Chlorophytum comosum)
-- Strawberry Begonia (Saxifraga sarmentosa)
-- African Violet (Saintpaulia sppClub Moss (Lycopodium spp.)
-- Emerald Ripple Peperomia (Peperomia caperata)
-- Flame Violet (Episcia diantheflora)
-- Creeping Charlie (Pilea mammularifolia)
-- English Ivy (Hedera helix)
-- Miniature Begonia Rex (Begonia rex-cultorum)
-- Watermelon Peperomia (Peperomia sandersii)
Taller growing plants. These are suitable for background plantings. Some may need cutting back to control size.
-- Heart-leaved Philodendron (Philodendron scandens)
-- Prayer Plant (Maranta leuconeura)
-- Aluminum Plant (Pilea cadierii)
-- Artillery Plant (Pilea microphylla)
-- Golden Pothos (Scindapsus aurea)
-- Pitcher Plant (Sarracena spp.)
-- Pink Polka Dot (Hypoestes panguinolenta)
-- Asparagus Fern (Asparagus plumosus)
If creating an outdoor scene, the selective placement of any of these items will enhance the looks of your terrarium. Generally, the larger containers are used for this purpose. Those who go beyond the beginner stage find many resources available and suitable for an elaborate woodland scene or a desert vista.
-- Logs. A decorative piece of wood resembling a fallen log adds interest to a terrarium.
-- Pools. A carefully placed mirror with soil and plants paced irregularly around the edges serves as a reflecting pool.
-- Rocks. Smooth river stones, colored rock or natural rocks that have character to them can be used effectively in a terrarium.
-- Other items. Many ceramic pieces of artwork can be used to add texture and diversity to the created scene in a terrarium. Let your imagination be your guide. There are no hard and fast rules.
-- Plants. Before placing plants in your terrarium it is a good idea to arrange them in an open space about the size of the container. This will give you a beforehand idea of what the terrarium will look like upon completion. Generally low-growing plants are placed in the front, then medium-sized plants, followed by the taller ones to give a pleasing gradation in sizes if your terrarium will be viewed from one side.
1) NEVER place your terrarium in full sun.
2) Add water whenever the soil gets too dry.
3) Fertilize your plants with a weak solution (1/4 the suggested amounts) of a water-soluble complete fertilizer. Terrarium plants tend to grow slowly and fertilizing them is not often needed. If the plants do not look as green or as healthy as when first placed, fertilizing them is called for.
4) Occasionally a plant may need some pruning to eliminate dead leaves, sucker growth and wayward shoots.
5) When any plant gets way too large or diseased, replace it with another. It’s easy to do. Consider potting it up and using it for a houseplant.
-- Use a sterile potting mix.
-- Wash the container before use.
-- Fertilize your plants only as needed.
-- Check all plants for pests and diseases before installing in the terrarium.
--When large drops form on the glass cover, you may need to leave the cover off for a few hours to let the air dry out a little.
-- Use glass, clear plastic or Saran wrap as a cover for the terrarium. Glass can be cut to the shape of the top.
-- Keep your terrarium out of direct sun.
-- Add water only when the soil dries out a little.