In the world of gardening, trends come and go, and sometimes the most fabulous trends become, well, trendy again. This is definitely the case with terrariums– the new “in thing” for indoor spaces.
These modern day miniature gardens under glass, just like their 1970’s counterparts, can be just as elaborate and complex as you want to make them. Here are a few tips we have learned along the way.
The first step is to select a glass vessel to house your creation. Choose any glass container without drainage. It could be anything from repurposed old apothecary jars, decanters, or bottles, to modern vases or containers—even an unused aquarium would fit the bill. Selecting the glass container is part of the fun. Unless you are a master with chopsticks, or have extremely tiny hands, a larger opening or removable lid will make the process a lot easier. Even though building a ship in a bottle is possible, a wide-mouthed opening will allow easy access for building, editing, and caring for your creation.
Because terrariums do not have drainage holes, spread a 1-3 inch layer of small pebbles or stones on the bottom of the container so water can drain from the soil above. Add a layer of horticultural charcoal on top of the pebbles to help filter the water and air within the terrarium as organic matter decomposes. Add a good, well-drained potting soil and you are ready to plant.
Terrariums are miniature ecosystems requiring all the same things that a full sized garden would need, but on a much smaller scale: light, moisture, nutrition, and editing. The key is to choose plants with similar light, moisture, and humidity needs. For instance, a terrarium with a smaller opening or removable lid would be a perfect environment for high humidity loving ferns, club mosses, Venus fly traps, baby tears, creeping fig, pilea, miniature begonias, Swedish ivy and tiny bromeliads. These are just some of the plants that could coexist in your terrarium. Air plants (epiphytes), like Tillandsias and interesting mosses, will further complement this mix of plants. You can also create dryer ecosystems in more open containers where moisture cannot collect by choosing a more drought-tolerant mix of succulents like aloe, agave, sedum, miniature pencil cactus, echiveria, etc. With whatever plant group you choose, make sure their needs are compatible. Combine plants with various heights, forms, textures, and colors for best visual results. Accessorize with stones, shells, sticks, and pods to create your own custom landscape.
In a more closed terrarium with a smaller or removable lid, very little water is needed. Moisture will collect on the sides of the glass and drip back into the terrarium while adding to the high humidity. When the plants need watering, do so gently, being careful not to add too much. Remember, there is no drainage, so usually err on the side of too little versus too much water. The more open the container, the more you will need to water. Once an equilibrium is reached, moisture in the terrariums will be nearly self-sustaining.
Just like any garden, a little editing and care will ensure a healthy environment for all the plants in the terrarium. Fertilize sparingly to discourage excessive growth. Don’t be afraid to snip back plants that are growing too fast. There is a bully on every playground, even in the plant world, so it will be your job to look out and protect the less vigorous plants from being consumed by the others.
Sounds pretty easy, doesn’t it? It might be time to let a terrarium provide a big green thumb imprint in your life. Taking little room, their foot print is as tiny as the self-sustaining ecosystem within their clear walls. Be inspired by some of the terrariums we put together at the garden center, and we will help you put together your own. It is what we do. How long will the terrarium craze last? Who knows, but we suspect quite a while, whether these gardens behind glass remain in vogue or not.
Scott Endres is co-owner of Tangletown Gardens and Tangletown’s WIse Acre Eatery on 54th and Nicollet in South Minneapolis.