A terrarium (plural: terraria or terrariums) is usually a sealable glass container containing soil and plants that can be opened for maintenance to access the plants inside; however, terraria can also be open to the atmosphere. Terraria are often kept as ornamental items. A closed terrarium's transparent walls allow heat and light to enter, creating a unique environment for plant growth. Heat entering the sealed container allows the creation of a small

water cycle The water cycle, also known as the hydrologic cycle or the hydrological cycle, is a biogeochemical cycle that describes the continuous movement of water on, above and below the surface of the Earth. The mass of water on Earth remains fairly cons ...

due to evaporating moisture from the soil and plants. The water vapor then

condenses Condensation is the change of the state of matter from the gas phase into the liquid phase, and is the reverse of vaporization. The word most often refers to the water cycle. It can also be defined as the change in the state of water vapor to ...

onto the walls of the container, eventually falling back onto the plants and soil below. Light passing through the transparent walls, allowing

photosynthesis Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored i ...

, with the constant water supply provide an ideal environment for plants. Open terraria are not sealed and are better suited to plants requiring a more arid environment.

History

The first terrarium was developed by botanist

Nathaniel Bagshaw Ward Nathaniel Bagshaw Ward (1791 – 4 June 1868 in St Leonard's, Sussex) was an English doctor who popularised a case for growing and transporting plants which was called the Wardian case. Biography Ward was born in London to Stephen Smith W ...

in 1842. Ward had an interest in observing insect behaviour and accidentally left one of his jars unattended. A

fern A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes exce ...

spore in the jar grew and germinated into a plant, becoming the first known terrarium. The trend quickly spread in the

Victorian Era In the history of the United Kingdom and the British Empire, the Victorian era was the period of Queen Victoria's reign, from 20 June 1837 until her death on 22 January 1901. The era followed the Georgian period and preceded the Edwardia ...

amongst the English. Instead of the terrarium, it was known as the

Wardian case The Wardian case was an early type of terrarium, a sealed protective container for plants. It found great use in the 19th century in protecting foreign plants imported to Europe from overseas, the great majority of which had previously died from ...

. Ward hired carpenters to build his Wardian cases to export native British plants to Sydney, Australia. After months of travel, the plants arrived well and thriving. Likewise, plants from Australia sent to

London London is the capital and List of urban areas in the United Kingdom, largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary dow ...

using the same method were received by Ward in pristine condition. His experiment indicated plants can be sealed, without ventilation, and continue thriving. Wardian cases were used for many decades by

Kew Gardens Kew Gardens is a botanic garden in southwest London that houses the "largest and most diverse botanical and mycological collections in the world". Founded in 1840, from the exotic garden at Kew Park, its living collections include some of the ...

to ship plants around the British Empire and were also used during European colonization of Africa to bring African goods, like spices and coffee, back to Europe.

Types

Terraria are typically classified into two categories: closed and open. Closed terraria are sealed shut with a lid, door, or cork; open terraria have access to fresh air, most commonly by leaving the container open or through a hole drilled into the container.

Closed terraria

Diagram of sealed terrarium Tropical plant varieties, such as moss,

orchids Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Along with the Asteraceae, they are one of the two largest families of flowering ...

ferns A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes except th ...

, and air plants are generally kept within closed terraria to replicate their native humid, sheltered environment in the tropics. Keeping the terrarium sealed allows for circulation of water, making the terrarium self-sufficient. The terrarium may be opened once a week, allowing evaporation of excess moisture from the air and walls of the container, to prevent growth of

mold A mold () or mould () is one of the structures certain fungi can form. The dust-like, colored appearance of molds is due to the formation of spores containing fungal secondary metabolites. The spores are the dispersal units of the fungi. Not ...

or algae, which may damage plants and discolor the sides of the terrarium.

Springtail Springtails (Collembola) form the largest of the three lineages of modern hexapods that are no longer considered insects (the other two are the Protura and Diplura). Although the three orders are sometimes grouped together in a class called Ento ...

s may be used to consume mold or fungi within the terrarium. Any wilting plants or absence of condensation on the walls of the terrarium indicates the terrarium requires water; watering is primarily done using a spray bottle. Closed terraria benefit from specific soil mixes to ensure ideal growing conditions and reduce risk of microbial damage; a common medium used is ''peat-lite:'' a mixture of

peat moss ''Sphagnum'' is a genus of approximately 380 accepted species of mosses, commonly known as sphagnum moss, peat moss, also bog moss and quacker moss (although that term is also sometimes used for peat). Accumulations of ''Sphagnum'' can store wa ...

vermiculite Vermiculite is a hydrous phyllosilicate mineral which undergoes significant expansion when heated. Exfoliation occurs when the mineral is heated sufficiently, and commercial furnaces can routinely produce this effect. Vermiculite forms by the we ...

, and

perlite Perlite is an amorphous volcanic glass that has a relatively high water content, typically formed by the hydration of obsidian. It occurs naturally and has the unusual property of greatly expanding when heated sufficiently. It is an industrial ...

. The mixture should be sterile to minimize risk of introducing potentially harmful

microbes A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in olde ...

to the terrarium.

Open terraria

Not all plants require or are suited to the moist environment of closed terraria; open terraria are better suited for plants preferring less humidity and soil moisture, such as temperate plants and plants adapted to dry climates. Open terraria also work well for plants requiring more (but not direct) sunlight, as closed terraria can trap excess heat, potentially killing the plants inside. While open terraria require more watering than closed terraria, they have reduced risk of disease due to their lower humidity. An open terrarium should not be confused with a dish garden. A terrarium, even open, allows for increased humidity compared to the environment outside the structure, whereas a dish garden does not provide additional humidity. Due to the transparent walls of terraria causing magnification of the sun's rays, terraria cannot be placed in direct sunlight because the intense light will cause foliage to burn. A dish garden can tolerate direct sun, as long as it is planted with full sun-tolerant plants. Succulents and cacti are better suited for a dish garden than a terrarium because dish gardens allow succulents and cacti to be placed in the full sun they require without burning.

References

External links