As winter settles in, the frigid temperatures and bleak, lifeless landscapes give some gardeners chills at the very thought of toiling outside. This winter, bring the warmth and vitality of summer indoors with you. Make the most of your yard’s dormant period by creating exclusively new gardens, or terrariums, inside your home.
Potted houseplants certainly add comfort and interest to the home, but they are no match for lush indoor gardens. A terrarium is a collection of compatible plants grown in an enclosed or partially enclosed, clear container. If you have never built one, designing a terrarium is a fun and exhilarating way to grow a miniature landscape inside your home. They can be grown in almost any room—the living room, bathroom, kitchen, or home office. In addition, these small-scale gardens prove to be the perfect solution for apartment dwellers, since terrariums quickly add color and life to even the smallest of balconies. Requiring little effort and attention on the gardener’s part, they are the ideal gift for those with demanding schedules as well; depending upon your container, terrarium plants thrive with little to no water.
The Right Container: Creativity Counts
The possibilities of containers for your terrarium are almost endless, so let your imagination run free. Whether you prefer gothic themes and wish to create a garden within a tabletop cathedral, or you favor more Asian styles and settings, the choice is yours. You can use bottles, jars, aquariums, fish bowls, or even brandy snifters; however, if this is your first time, you may want to stick with large, open-mouthed containers and then advance to using chopsticks with smaller containers as you gain experience. If you are designing a terrarium for your child’s room, consider employing small bubblegum machines or candy jars. You cannot go wrong as long as your container is clear plastic or glass to allow sunlight to penetrate; creativity is half the fun.
Before you build your terrarium, make sure both the inside and outside of the container are clear. Remove any existing labels and wash the container with hot soapy water. Lids are crucial to enclosed gardens, so employ a sheet of plastic (like saran wrap) or a decorative stone as a cover if your container does not already come with one. Succulent terrariums do not require lids, since they prefer a drier atmosphere.
An enclosed garden enables you to grow plants that call for a high degree of humidity. Once the plants become established, the terrarium begins to create a climate of its own. The plants transpire moisture through their leaves, which then condensates on the glass and flows back to the soil. This natural rain effect allows terrariums to go for weeks without watering.
Building your Terrarium: Layers of Life
The longevity of your terrarium depends largely upon its foundation. For a successful garden, your groundwork should consist of four layers. The bottom layer, composed of pea gravel, pebbles or sand, provides drainage. Proper drainage is essential to ensure that the soil does not become over saturated, a problem which leads to root rot and possibly the death of your plants. Depending on the size of your container, spread at least an inch of drainage material evenly across the entire bottom. Large or deep containers can hold up to three inches of gravel or sand.
On top of the drainage layer, spread a thin layer of activated charcoal; this will help clean the air of the fumes caused when the organic materials begin to decompose. Next, cover the charcoal with a thin layer of sphagnum moss. The moss aids in soil retention, since its purpose is to prevent any soil from sifting down into the drainage layer, which would thereby render it useless. The fourth and final level is your soil. Some garden centers offer a premixed terrarium soil, which you can use if you prefer. Otherwise, simply add one part coarse builders sand and one part humus to each two parts of your planting soil. Add extra sand to the mix and additional gravel to the drainage level if you intend to create a desert garden.
Although the bottom three layers should be spread evenly, keep in mind that the terrarium will seem more realistic if you add contour to the landscape with different levels of soil. Incorporate your own decorative stones or pieces of wood as garden accents, just as you would in your outdoor landscape. Let your imagination come to life as you create terraces, valleys, and hills to flow freely through the terrain. If you plan to add any critters like lizards or tarantulas, remember to include a miniature lake within the landscape to offer them a spot to drink; this can be made out of any shallow dish depressed into the soil.
Planting: Miniature Gardens with Bold Appeal
Select your terrarium plants for their compatibility in light, water, and humidity needs. Consider also their varying heights, shapes, textures, and colors to create the desired landscape effect; small specimens of slow growing plants work best. Design the landscape so as to offer the best visual effect. For instance, if the garden will be viewed from all sides, set a large plant in the center, while integrating shorter plants around it. On the other hand, if your terrarium will primarily be seen from only one side, position the tallest plant near the back of the container, and group smaller plants in the foreground.
Before planting, arrange your plants in the terrarium until you have achieved the desired effect; as with outdoor gardening, it is much easier to move plants while they are still in pots. When working with narrow mouthed containers, you may want to draw any landscape ideas on paper.
Once you have created your design, remove the plants from their pots and set them in their predug holes. Do not loosen the plants’ roots however, since this encourages quicker growth rates. Take care not to crowd the plants or place them directly against the sides of the container. Slightly moisten the soil after planting, and place the lid on your terrarium.
Keep your miniature garden out of full sunlight and refrain from adding any fertilizer; your planting mix holds enough nutrients to last almost the lifetime of the terrarium. If the plants later appear malnourished, try feeding them with a weak solution (1/4 strength) of an all purpose houseplant food. As far as watering is concerned, a completely enclosed terrarium requires little or no watering. If it is partially open however, you may have to water on a weekly or monthly basis; water more frequently for completely open terrariums or dish gardens. Remember that extra water is only necessary—and should be added in small amounts—when there is no condensation on the glass.