Enjoying Outside, Inside - Terrariums

Kristie Ehrhardt • September 28, 2023

A terrarium is an indoor garden. It is generally in a glass container and can either be sealed or open to the atmosphere. Sealed terrariums usually contain plants that thrive in warm, humid environments while an open terrarium can support many other types of plants including those typically found in arid environments. They are useful for plant propagation as well as plant and animal observation but mainly they are just a lovely bit of outdoors made for indoor enjoyment. Even those that may consider their thumbs a little less than green can usually keep a terrarium healthy.


A sealed terrarium requires very little maintenance because they are primarily self-sustaining. As the moist soil and plants release water vapor it is collected on the walls of the terrarium and runs down back into the soil to be used again by the plants thus, recycling the water in the sealed container. A sterile soil mix containing peat moss, vermiculite and perlite is a good growing medium for all terrariums. This mix provides the ideal growing conditions for tropical plants while reducing microbial growth. Slow growing, tropical plant species typically do the best in sealed terrariums as the conditions in the container mimic their native, warm and humid environments. Moss, small ferns, carnivorous plants, orchids and air plants do well. In fact, air plants can be very difficult to propagate outside of a sealed terrarium. If too much water vapor collects, the container can be opened once a week to allow some fresh air to enter and hinder the growth of algae or mold. If the plants look wilted or you don’t see any water droplets on the sides of the container, this may indicate that the terrarium is too dry. A spritz with a spray bottle is the best way to give them a little drink. Fun fact, cute little springtails may be used to consume mold that may be growing inside your sealed terrarium. Here is an article if you’d like to learn more about springtails and terrariums.


If you prefer to use plants that like a less humid environment an open terrarium would be a great option. Open terrariums also work well for plants that need more sunlight as sealed terrariums trap heat and can get too warm if exposed to a lot of direct light (think greenhouse effect). Open terrariums also have a reduced risk of disease because of their lower moisture content. However, they do need to be watered more frequently due to evaporation and exposure. Usually watering only every three to six weeks is enough but it’s best to check the soil moisture rather than water on a schedule. The types of plants and how many there are will help determine how often to water as well. If you over-water your terrarium may get gnats or mealy bugs. If this does happen, insecticidal soap can help get rid of them without harming the plants but simply not overwatering is the best plan.


If you’d like to try making your own sealed or open terrarium, you’ll need a transparent container (plastic or glass), growing medium, pebbles for a drainage layer, activated charcoal, decorative rocks, wood or moss (if you’d like) and plants that will stay fairly small and are suited for the type of terrarium you’d like to make. Empty aquariums, fish bowls, vases or even an empty soda bottle work nicely for containers. Fill the bottom of your container with the pebbles. Since there are no drainage holes in a terrarium, you’ll need to provide something to keep the plants roots from getting soggy. Next put down a layer of activated charcoal to help with drainage and any musty odors that might occur. Then, fill your container with a thick layer of the growing medium but reserving some to fill in around the plants. Make divots in the soil for each plant deep enough for them to stand upright and still allowing room for the roots to be able to spread. Then, add more of the growing medium around them and press it all down slightly to help the plant stay stable – it should be buried about as deep as it was in its nursery pot. You can then add pebbles, larger rocks, moss, wood or any other decorative items you’d like. The types of plants you chose will depend on whether you want to make a sealed or open terrarium. If you’re ready to make your own terrarium, here is a thorough article on how to make your own. Enjoy your mini garden inside, all year long!


-Kristie Ehrhardt (kehrhardt@tuleyome.org)


Tuleyome Land Conservation Program Manager


RECENT ARTICLES

By Ellen Jenkins July 2, 2026
From left to right, Horticulture Interns Ellen Jenkins, Rithika Warrier, and Diego Barraza Hernandez, with Education Associate Geoff Benn, who coordinates the internship program. From September to June, I worked as a Horticultural Intern at Tuleyome. Each week at the Woodland Regional Park Preserve, I would meet with my mentor Teri Barry. Over the course of the year, we worked together identifying, documenting, and analyzing the preserve's growth. Through this opportunity, I gained experience in hands-on restoration efforts, familiarity with plant taxonomy and classification, and community outreach.
By Kristie Ehrhardt July 2, 2026
I’m sure you already know that the Bald Eagle is used as a symbol of our Nation’s freedom, strength, perseverance and independence. It is said that our founding fathers chose the Bald Eagle to adorn our Great Seal because it is indigenous to North America and if you look closely at it, you’ll see that it is holding 13 arrows and an olive branch simultaneously symbolizing the power of war and the power of peace. But, what about our national mammal? Er, maybe you didn’t even realize that we had a national mammal… President Barack Obama designated the American Bison as our national mammal in May of 2016. It too is endemic to North America and in prehistoric times, millions of them roamed through roughly two-thirds of the United States. Their range was known as the “great bison belt” - a stretch of habitat that encompassed the forests of Alaska, the grasslands of the North American plains and stretched from the Great Basin east to the eastern Appalachian Mountains. Side note - I’m just gonna come clean right now and tell you that the historic range of the American bison, American Buffalo or just plain bison or buffalo does NOT include the Berryessa Snow Mountain National Monument (Monument). I’m supposed to be writing about the Monument region and I picked a topic that is clearly not there but it’s important and they are impressive so please don’t tattle. Another side note - the American Bison and the American Buffalo are one in the same and both names can be used interchangeably. Its scientific name (genus and species) is actually Bison bison so I guess calling them bison is probably more scientifically accurate but either works. Bison are North America’s largest land animal; an adult male averages about 2,000 pounds - that’s a ton (thanks Schoolhouse Rock, I will never forget this one!), are about 12 feet long from nose to rump and about six feet tall. Females max out at around 1,000 pounds and are a little over nine feet long. In the wild bison can live ten to twenty years. Both females and males have massive forequarters and sport what looks like a shaggy, long-sleeved sweater. Both sexes have short, curved horns that are an integral part of their status in the herd and defensive strategy. During the snowy winters, bison display a dark brown winter coat and in the summer they show off their lighter brown summer-bods. Calves typically arrive from March through May depending on weather conditions. When they’re first born calves are an orangey-red color which earned them the nickname “red dogs”. Within a few months they become darker brown like their parents and their little horns start to poke through. Around this time they also begin to develop their iconic shoulder hump. The hump is made of solid muscle buttressed by elongated vertebrae. This dense network of muscles act as a powerhouse that allows the animal to swing its massive head from side to side and plow through icy snow to access buried forage enabling them to survive even the harshest winters. Although they are not known for keen eyesight, bison have superb senses of hearing and smell. As monumental (get it?) as these animals are, they are shockingly quick and agile. Bison have been clocked at running 35 miles per hour (!), they can spin and turn on a dime, leap over high fences and are incredibly adept swimmers. All these mad skills on a strictly vegetarian diet - that’s ruminant efficiency. For thousands of years, before the European settlers arrived, Native Americans of all tribes and regions revered the bison. They were the cultural, spiritual and resource backbone of indigenous societies across the United States. Every part of the animal was used; the meat was consumed, the hide was used for clothing, shoes and shelters, and the bones and hooves were used for tools and weapons. Even the sinew was used for sewing and bow strings. Everything was copacetic then came the Europeans with their domestic cattle diseases and thoughtless greed. Bison were hunted to near extinction within roughly just 100 years. Their numbers went from an estimated 60 million (!) to less than 550 individual animals by 1889. They were hunted mercilessly and their habitat destroyed, some say as a way to control the Native Americans by removing their primary resource. One of the buffalo’s biggest fans was President Teddy Roosevelt. In the early 1880’s he traveled to what is now North Dakota (shout out to my people!) to hunt. After recognizing the bison’s diminishing population numbers he co-founded the American Bison Society in 1905 to help conserve and protect this American emblem. For many years the few buffalo that remained were only found in national parks and preserves but primarily on Native American reservations. Had it not been for the willingness of tribes across the country to work with interested individuals and state and federal governments, the American Bison would be gone today. Much like the Bald Eagle, the bison is an authentic symbol of American character and as it turns out, another one of the greatest conservation success stories in U.S. history. The bison within the Yellowstone National Park boundaries are direct descendants of the original animals that roamed our country’s grasslands and are the only herd that still occupy their original prehistoric location. This free-ranging herd numbers approximately 5,500 animals and is the largest herd on public land. Recovery efforts paid off and today bison can be found in all 50 states including private and tribal lands, national parks and wildlife refuges.