With some light pruning, refreshed leaf litter and a spray of clean rainwater, we tidied up one of our favorite terrarium displays this evening. 'Estonia' is built into a 37G Column enclosure (20" X 18" X 24") with plants and other features evoking a Baltic woodland with Birches, Firs and a ground layer of soft Ferns.
This model ecosystem is very easy to maintain and designed to endure for at least several years. An "egg crate" light diffuser plate supports a rooting substrate comprised mainly of porous gravel (similar to bonsai tree soil) and allows for free drainage and siphon removal of irrigation water. A groundcover of dried leaves, conifer cones and found objects creates a convincing forest floor microhabitat, while a trio of Birch tree poles reach to the top of the tank, providing vertical dimension and creating an appearance of mature canopy trees. A 12-volt fan, mounted on the glass with the Selva Terrarium Fan Mount Kit, provides internal air circulation with a gentle breeze.
Plant selection is simple with just three easy-to-grow choices. Northern Temperate Zone plants are usually difficult to grow indoors—most have strong winter dormancy cycles—but three "stand-in" plants create the desired effect. Mexican White Cedar (Cupressus lusitanica) is a conifer tree that responds very well to pruning; it is often planted as a trimmed hedge or Christmas tree. An evergreen, sub-tropical tree, Faber's Maple, (Acer fabri), was planted as just a single stem to represent a deciduous tree sapling. Korean Rock Fern (Polystichum tsus-simense) is an adaptable small fern requiring little more than good soil drainage and with the perfect size, shape, texture and growth habit for this kind of planting.
The terrarium planting was designed only for live plants and does not house livestock, but the antlered skull of a Roe Deer (Capreolus capreolus) lies hidden among the dried leaves and fern fronds to complete the effect of a cool, sun-dappled Baltic forest and its countless mysteries.