“Know from whence you came. If you know whence you came, there are absolutely no limitations to where you can go.” —James Baldwin
Dr. Ward shared his findings with his friends in the botany community, and before he knew it, fern fever was in full swing. Wardian Cases were manufactured in all sizes, from small portable cases for the amateur home collector to giant life-size versions called “ferneries.” Most significantly, Wardian Cases were instrumental in transporting live specimens across long ocean voyages. Thousands of Wardian Cases were used to import live tea trees from China to England, and we all know how much the Brits love their tea! Rubber trees were fetched from Brazil, which led to a prosperous rubber industry that played a crucial role in both World Wars.
However, as the saying goes, all good things must come to an end, and by the beginning of the 20th century the popularity of ferns dwindled and was subsequently replaced by orchid fever. Dr. Ward was certainly not the first person to invent the science behind a terrarium, but he certainly championed the cause and made plant collecting more accessible to the masses. In the end, what I find so remarkable is that all of this was born from nothing more than a little fern in a jar.
According to the American Fern Society, today there are over 10,000 species of ferns. Ferns are common enough that they are readily available for purchase at most garden centers and even farmers markets. In parts of the southern United States, Kimberly queen ferns adorn entranceways and Boston ferns hang from porch baskets. In New England, fiddlehead ferns are harvested in the spring and then cooked and served as a delectable regional specialty. With the popularity of terrariums on the rise, ferns are once again making their way under glass enclosures for our viewing pleasure!
A hanging Boston fern.
HOW A TERRARIUM WORKS
WHAT IS A TERRARIUM?
Terrariums are an eye-catching way to bring the whimsy of nature indoors. These mini indoor gardens are a great way to maximize space while adding a touch of greenery to your home. The conventional definition of a terrarium is a self-sustaining living ecosystem inside a sealed glass container. The high humidity inside an airtight container provides the right conditions for many tropical plants to thrive in your home all year long.
While there are some extraordinary exceptions, terrarium displays are not forever. Even with regular pruning and maintenance, plants tend to outgrow their containers and need to be repotted into larger containers. This means you get to go out and buy new plants for a new display, and that can be really exciting!
Take into consideration that not all plants can be kept under glass and not all species can be planted together in a terrarium. Tropical plants are best suited for closed containers while succulents, tillandsias, and cacti need the airflow that an open vessel provides. While not all the terrariums in this book are conventional terrariums (in fact most stray far off the beaten path), it’s important to understand some fundamental workings of a biosphere to really appreciate how amazing it is to cultivate life under glass.
Everything happening inside a terrarium is a miniature representation of all the amazing phenomena we experience in our own natural world. I’ve found that having some knowledge of plant biology is very helpful in maintaining healthy plants indoors. While we all learn about photosynthesis and the water cycle in grade school, I thought a little refresher would be helpful.
Carbon Dioxide (CO2) + Water (H2O) + Sunlight = Sugar (Glucose) + Oxygen (O2)
PHOTOSYNTHESIS
Plants create their own food through a process called photosynthesis. In the Greek language, photo means “light,” and synthesis means “to combine.” Plants combine water and carbon dioxide and use the energy from the sun to create their food. Plants have tiny openings in their leaves called stomata which open to collect carbon dioxide from the air. The water molecules from the roots and carbon dioxide from the leaves are then transported to the plant’s chloroplast cells where sunlight is collected. Here food is created for the plant in the form of sugar (glucose). Oxygen is a byproduct of this process (it’s lucky for us that it is) and at night the plant releases oxygen into the air through the process of respiration. Because it’s not polite to disturb plants during respiration, if you must add water to your terrarium or water your houseplants in general, try to do it in the morning.
CRISPY BROWN LEAVES
Q: What does it mean when leaves, especially along the edges, turn brown and crispy?
A: From what we know about transpiration and evaporation, water from the leaves is evaporating faster than the plant can transport water from the roots to the leaves, leaving them to dry out and lose their vibrant color. Your plants could be suffering from the soil being too dry, the air being too dry, or getting too much sunlight. Prune crispy leaves to allow the plant to focus its energy on healthy foliage.
THE WATER CYCLE
The water cycle is what sustains all life here on Earth. Without the water cycle, we would not have clouds or rain to provide fresh water to all living things. This process can be summarized into three different stages: evaporation, condensation, and precipitation. As the sun heats up our oceans, lakes, and rivers, water vapor is created through the process of evaporation. This warm water vapor rises into our atmosphere where it meets cooler temperatures. During the condensation stage, water vapor cools and transforms into clouds. Clouds become saturated with liquid water molecules and, when they can hold no more water, they release it back down to earth as precipitation. Rain, hail, and snow collect in bodies of water, and the cycle begins again.
THE WATER CYCLE INSIDE A TERRARIUM
The water cycle inside a terrarium is not much different than the one outside. The three stages are transpiration, evaporation, and condensation. In a terrarium, the glass vessel takes the place of our atmosphere by holding the soil, water, and all living things inside. First, water is transported from the roots through the plant’s leaves and released into the air through their leaves in a process called “transpiration.” As the sun heats up the vessel, water is evaporated into the air. If you look closely you may even see a light mist or fog inside. As the air inside the terrarium becomes humid, or saturated with water vapor, it starts to condense and create liquid water on the glass. Eventually the water slides down and back into the soil. The water is recycled over and over so there is no need to continuously water a closed terrarium.
SHOW ME THE LAYERS
Terrarium vessels do not have drainage holes, so it’s up to you to create a proper drainage system for your living display. In closed terrariums these layers play a crucial role in the water cycle. In an open container, they ensure proper drainage and keep plant roots from sitting in water for too long. The layers are presented in the order they should be followed.