A terrarium is a small ecosystem in a glass container, either sealed or open, made up of soils and plants. If sealed, it should be able to open up for watering and maintenance. A terrarium is typically used as a decorative piece but can also be educational. For example, a teacher could pair a terrarium-building activity with a lesson about ecosystems as a fun way to learn the information.
Step 1: Research
Which type of terrarium do I choose?
There are two types of terrariums: closed and open terrariums.
Closed terrariums have a lid to seal up the container, using evaporated moisture from the soil to create a small water cycle environment and be mostly self-regulating with little maintenance. Closed terrariums should not be placed in direct sunlight, as this intensity of heat can "cook" your plants and kill them. Closed terrariums should also be opened periodically (at least once a month for 10-20 minutes) to allow fresh air to populate the environment.
Open terrariums do not have a water cycle like closed terrariums, meaning they must be watered more frequently. The amount of watering necessary depends on the plant used and the layers contained within the terrarium, as some of them hold and dispel water at different rates.
What type of container should I use?
The decision on the type of container to use should be made as a result of the type of plant you wish to house, the type of terrarium you want (open or closed), and your overall aesthetic desired for the terrarium. If you want a closed terrarium, be sure to get a container with a lid. Glass or plastic is fine, just so long as the container is free of chemicals or unknown liquids, as these can kill the plants or attract bugs.
What type of plant do I use?
Both open and closed terrariums can house a variety of plants. However, closed terrariums are more popular for use with moisture-loving plants like ferns, ivy, and mosses, and are ideal for the user who wants to care for the plants minimally. Open terrariums are typically favored for normal house plants, succulents, and cacti. Succulents and cacti require very little maintenance, so these are popular for those who want an open terrarium with little maintenance. Overall, the type of plants to put in your terrarium is up to you, and research should be done on the needs of each specific plant as well as the size it will grow to so it does not outgrow your container.
Step 2: Materials
- Rocks, Pebbles, Gravel, or Sand
- Horticultural/Activated Charcoal
- Moss (Optional)
- Plant of Your Choice
- Optional: Decorations
Buy your rocks, charcoal, moss, and soil here.
Step 3: Preparation
- Be sure to lay down a cover over your work surface before beginning.
- Have on old clothes, put away anything that you do not wish to get dirty, and be prepared to get messy!
- Working with plants and soil is not a job for those afraid to get a little dirty.
- Charcoal leaves a dark residue on anything it touches, so be careful not to get it on anything besides your hands and the inside of the container unless you are prepared to wash whatever it touches.
- If your container has a narrow opening, have some type of aid to help you place the materials inside (such as a funnel, spoon, or something else you have laying around).
- Plan the amounts of each material you wish to put into the terrarium. It's hard to take out some of the bottom layer once the rest are in!
Step 4: Layer One - Rocks, Pebbles, Gravel, or Sand
Terrariums do not have a means of draining water. To combat this issue, a layer of rocks, pebbles, gravel, or sand should be placed in the bottom of the terrarium to provide a place for excess water to go. By providing a place for drainage, the terrarium will be much easier to maintain and will help your plants live longer and healthier due to being provided an appropriate amount of water. The material used from the list above does not really matter, but should coincide with your aesthetic or theme desired for the terrarium.
Step 5: Layer Two - Charcoal
Since many terrariums are closed and do not have a way of dispersing old air until opened, a layer of charcoal should be added to keep things in the terrarium fresh. Adding charcoal is a good idea even if you are not using a closed terrarium, as excess water can begin to cause bacteria and mold to grow in the drainage layer whether in an open or closed environment. The charcoal acts to prevent these organisms from growing, as well as add a bit more protection for the drainage layer to keep plant roots from reaching the excess water.
Step 6: Layer Three - Moss (Optional)
A layer of sheet moss keeps the top layer of soil from working its way into the bottom layer of pebbles. Preventing the soil from moving into the drainage area is a good step for the aesthetics of the terrarium as well as the functionality of it. Aesthetically speaking, it keeps the terrarium from looking muddy, while functionally speaking, the soil stays where it needs to so that the plant stays nourished. Also, as a bonus, you do not have to keep adding soil once it moves to the bottom of the terrarium, nor do you have to try to work past all the other layers to clean out the bottom one.
Keep in mind, this step is not required for a good terrarium. Some people feel that the moss holds excess water and can become moldy, so whether or not you decide to include this step depends on personal preference. It also depends on the type of plant that you choose. A plant that does not need a lot of water may not do well with the excess water the moss holds, but you may decide that a plant that requires a lot of water would benefit from this layer.
Step 7: Layer Four - Soil
Just like with any plant, the one in your terrarium will need soil for it to grow. You want the soil layer to be thick enough for the roots to grow down into it, but not so thick that it holds too much water because that can cause mold to grow. A general amount of soil that you should strive for is approximately 25% of the container you are using.
Step 8: Add Plant(s)
The final step required for building your terrarium is to add your plant, or plants if the container you chose is big enough to hold multiple. To reinstate what was mentioned earlier, your plant needs to make sense with the type of container you have and the type of soil you plan on using. If you have enough room for multiple plants, you need to make sure that all the plants are similar. It would not make sense, nor would it make things easy, to have multiple plants that each need different amounts of water, light, or grow too large.
Step 9: Maintenance
To keep your terrarium looking healthy and beautiful, you must take care of it on a regular basis. Other than watering your plants an appropriate amount, some things you can do to help keep your terrarium clean are trim your plants so they do not outgrow your container, remove any dead leaves and plants from your terrarium, and remove and keep out any algae or mold.
Something extra you may want to do if you choose to have a closed terrarium is ventilate it every couple of weeks. Even though this type of terrarium is fairly self-sustaining, it should not just be forgotten. Open the container for a few hours to let it "breathe" then close it back up. If there is condensation then it is still good to sustain itself, but if condensation does not occur, now is a good time to give it some more water.
Step 10: Optional: Decorations to Make It Your Own
Decorating your terrarium is completely up to personal preference. You can put as little or as many trinkets in your terrarium as you desire. Just as an example for the sake of these instructions, you can see that we placed a few shells in our terrarium. Adding these, or any decoration, is purely for aesthetic purposes.
Giving your terrarium a theme is also completely up to personal preference. For example, if you want a cactus as a plant, you may want to give your terrarium a desert theme by using sand instead of pebbles or not including the layer of moss.
Step 11: Voila! You Now Have Your Very Own Terrarium!
You have completed the construction of your terrarium. Using the various layers to ensure your plant's health and maintaining the terrarium properly will provide you with a healthy organism ready to thrive in your kitchen, bedroom, dorm room, classroom, or anywhere else you believe needs a bit of nature. Thank you for using our step-by-step guide to creating your own terrarium. Be sure to give us a rating and come back for more how-to's on your favorite classroom and home projects. Thanks!