April 3, 2018 > Looking through the terrarium glass
Looking through the terrarium glass
By Daniel O'Donnell
Life is just as busy today as it was in 1829. So, it?s not surprising that Dr. Nathaniel Bradshaw Ward, a botanist/entomologist, would forget about a sealed jar he filled with a little soil and a moth pupa. Sometime later he stumbled upon the jar and noticed there was some grass and a fern growing in it. This jar inspired him to create a line of airtight containers that plants could grow in. They were referred to at the time as Wardian cases; today they are called terrariums.
Dr. Ward's glass jar was the first time that plants were grown in an airtight environment. This would dramatically change the world of botany because exotic plants could now survive long journeys. Terrariums were not only important for scientific research, but quickly became a trendy hobby among English households. Terrarium trends have since come and gone, including their resurgence in the U.S. during the 1970s. Today there are countless ways to occupy personal time, and building terrariums is still one of them.
There are two types of terrariums: a closed terrarium that is sealed off to outside air or an open-sided terrarium that allows air to circulate freely. Both types can be visually stunning and fun to create, however their constructions will differ.
A closed terrarium creates a habitat independent from the one outside. The clear glass allows light to come in for plants to photosynthesize and to generate heat that will create a mini water cycle. Even the most efficient closed terrariums will need to be opened occasionally to refresh the air or allow the excess water vapor to escape if there is condensation.
A closed terrarium starts with an airtight glass container. The size and shape of it are entirely arbitrary. A glass wine carafe, large mason jar, or clear cookie jar are just a few of the diverse options. The wider the opening, the easier it will be to create and maintain. Long tweezers may be necessary if the opening is too narrow for a hand to fit through. Small openings also limit the inorganic items that can be incorporated into the terrarium setting, such as rocks, driftwood, miniature statues and figurines, or tiny structures.
Construction of a closed terrarium begins with a one- to two-inch layer of gravel to collect water that has passed through the soil. A one-inch layer of activated charcoal (found in most pet store fish departments) placed on top of the gravel will provide air and water filtration. Next, add a layer of potting soil deep enough to plant in but leaving plenty of air space for the plants to grow into. Add the plants and any rocks, colored gravel, or ceramic figurines that will personalize the terrarium. Water the plants and close the lid. The terrarium should be placed in a location that gets plenty of indirect sunlight.
The plants used in a closed terrarium will be primarily limited to ferns, mosses, and tropical plants due to the high humidity of the sealed environment. There is a greater scope of plants that can be used in an open-sided terrarium. They range from succulents and cacti that prefer dry desert conditions to sub-tropical houseplants that like their environment moist. The size and number of plants will depend upon the size of the terrarium, regardless if it is closed or open-sided.
An open-sided terrarium will have the mouth of the container on the front side. This makes it harder to create from a household object than it is to simply purchase. There are a wide variety of ready-made shapes and sizes available. Planting any open-sided terrarium begins with a thin gravel layer followed by a layer of potting soil that is conducive to the needs of the plants. Open space is an important design element, so do not over plant. The non-planted space gives an opportunity to create vibrant patterns with colored sand or polished gravel paths. An open-sided terrarium can be placed anywhere that meets the light requirements of the plants.
Open-sided terrariums can also be used to create miniature themed worlds by pairing plants with objects that echo the motif. Bright green moss, a small clump of Mondo grass, some feather rock, and a miniature pagoda will create a Japanese-style terrarium. Baby tears, purple Spiderwort, small ceramic mushrooms, and a gnome will portray a fanciful theme. Any small figurine or art piece is fair game for making a personalized terrarium.
A wide variety of terrarium planters can be purchased at Succulence in San Francisco (www.thesucculence.com). Succulence has an extensive inventory of terrarium appropriate plants, polished gravels, brightly colored sands, and they host terrarium building classes. If the class schedule is not suitable, they have a DIY planting bar with whatever supplies and expert advice might be needed.
Do not be afraid to indulge in the delightful hobby of building terrariums. Dr. Ward's first terrarium was a happy accident and it turned out fine.
Daniel O'Donnell is the co-owner and operator of an organic landscape design/build company in Fremont. www.Chrysalis-Gardens.com