Trends have a way of recycling themselves. Creating terrariums, an old trend from the 1970s, is popping up again.
Terrariums were first created by Dr. Nathanial Ward, an English physician and botany enthusiast, for germinating ferns from spores. He created a closed glass case, named the Wardian case, that was pretty much a miniature greenhouse. The case proved useful to plant collectors wanting to bring plants back to England from far away places and also became popular in home decorating.
The large glass terrarium in my garage is proof that I enthusiastically participated in the terrarium trend of the ’70s. Terrarium purists will tell you that a terrarium is planted in a transparent closed container. Not long ago, I talked about miniature dish and fairy gardens. A terrarium is similar, but the garden is placed inside a clear container, such as a large glass jar, big bottle, fish tank or giant goblet. Clear plastic containers may also be used.
I recommend a container that is large enough to accommodate the plants and one that has a large enough opening to facilitate planting the terrarium. If the opening or neck of a container is narrow, planting within them is like trying to build a ship in a bottle, possible but difficult.
Start by cleaning the inside of the container and when dry, add soil to the container. Use an artificial potting mix, preferably one containing peat moss, perlite and sand. There is no need to add gravel or other coarse material for drainage, like what was recommended in the ’70s, because these materials actually hinder drainage.
Moisten the mix first because it is difficult to moisten once it is in the container. How much mix is needed? There should be enough mix to accommodate plant roots, but generally it does not need to be any deeper than 3 inches even in large containers.
Finding and selecting suitable plants may be a challenge. Seek dwarf and miniature plants that will stay small or slow-growing ones that will not outgrow the container. Choose ones that are similar in their growing requirements, such as humidity, light and soil moisture. Plants of with heights, texture and leaf color will provide the most interest in your design.
When ready, remove the plants from their pots and loosen the roots. Plant the largest and tallest plants first, and then arrange the smaller plants around them to provide a pleasing landscape design. The plants will grow, so take care not to use too many or place them too closely together. Moss or prostrate trailing plants can make attractive ground covers. If desired, add some decorative accents such as small rocks or figurines.
After finishing your planting, rinse any potting mix off the container sides and plant leaves using a spray bottle, taking care not to add too much water. Place the lid on the container or use clear plastic wrap to close it. Situate the terrarium where it will get lots of light but not direct sunlight.
Your terrarium may exhibit condensation. However, if the condensation is excessive or continues past a week or two, vent the container a little each day until it stops. After that, water occasionally and prune plants when they start to grow too large, but you should be able to enjoy your terrarium without constant attention.
My favorite plants for a terrarium? They are miniature African violets and their relatives, miniature Gernerias.
Marianne C. Ophardt is a horticulturist for Washington State University Benton County Extension.