If you’re stuck at home looking for a new hobby to pick up, I’ve got great news for you. Terrarium building is a great way to spend your time.
A terrarium is essentially a mini ecosystem in a container. It’s a very low maintenance way to raise plants indoors while allowing you to display your creative side at the same time. To make a terrarium, you just need five components: a container, drainage layer, separation material, substrate, and plants that love high humidity and low light.
So without further ado, let’s get into how you can build your first terrarium.
Table of Contents
Quick Start Terrarium Guide
If you want to skip the reading and just get started, you’re going to want to start with this section. It covers all the essential steps you need to build a terrarium from scratch completely free. You can also print out my step by step checklist here to follow along.
Gather a few things from home:
- Grab an empty jar or plastic container
- Grab a plastic bag and some scissors
- A few pieces of paper or newspaper (recommended)
- A spray bottle (recommended)
- Small decorative items (optional)
Get a few things from your backyard or nearby park (with a bag to carry things):
- Rocks (to fill your container about 1.5 in high)
- Soil (to fill your container about 2 in high)
- Small plants and moss
- Twigs and pinecones (optional)
Assemble the terrarium:
- Fill your container with rocks up to about 1.5 inches
- Cut out a section from the plastic bag that’s slightly larger than the bottom of your container
- Poke small holes in the section of plastic bag
- Place the cut out section on top of the rocks in your terrarium, curving the edges upward along the container walls
- Using your paper as a funnel, pour the soil into your container until roughly 2 inches high
- Dig small holes for any plants with roots and add your plants on top of the soil
- Give your plants a few spurts of water
- Add any decorative items to your terrarium
- Seal the container with a lid (if building a closed terrarium)
So that’s how you build a terrarium from scratch. But if you want to hear about all the details of why you are doing what you are doing and what other choices you have in that process, feel free to read on.
Materials you will need to build a terrarium
Before we get into the detailed steps you need to follow to put your terrarium together, the first thing you will need to do is gather your materials. It’s going to save you a lot of time if you have all your materials all in one place rather than running back and forth to get them as you need them.
Here’s what you’ll need (and roughly in this order):
- A container
- Some small rocks or sand
- A synthetic mesh or thin piece of plastic
- Potting soil
- Plants for your terrarium
Some tools that might be helpful:
- A funnel
If you’re thinking about doing some shopping and buying these components online, I would estimate it’s going to cost about $30 on the low end. For more info about that, you can reference my detailed pricing guide.
But if you don’t want to spend too much money, you can get a lot of these materials for free from stuff you might have at home or from a local park or trail. My pricing guide also has some more details about how you can do that as well.
If you’re not sure what each of those materials are for or why we need them, I’ll explain as we go in this article. You can also check out this article on the basic components of a terrarium for more details.
Depending on what kind of terrarium container you are using, you may want to look into getting some tools to help you out. The main thing that you want to think about is how big the opening to the container is. If it’s too small to fit your hands in, it’s going to make your life a lot easier to invest in some nice tweezers to help you out when constructing your terrarium.
Check out my recommendations for tools if you’re not sure.
Choose a terrarium container
Get a mason jar, a plastic bin, a plastic container, or a glass jug that has some kind of mouth or opening.
For closed terrariums, you will want something that can be sealed off with a lid of some sort. Open terrariums do not necessarily have to have a lid available to close it off.
For choosing your terrarium container, it’s pretty hard to go wrong as long as you’re choosing something that is clear and transparent. For the most part, this means some kind of plastic or glass container.
The concept of the container is that it encloses the air and moisture around your plants, preventing water from escaping, allowing it to form a self-contained water cycle within your terrarium. As long as it does that job without blocking light from reaching your plants, it should be good to go.
If you can, try to choose a container that’s on the larger side. That’s going to make it a lot easier for you to handle your plants and perform maintenance on your terrarium in the future. It also gives you a larger margin for error. Any effects of overwatering or underwatering or disease will be less extreme and less widespread/more localized in a larger terrarium.
At the very least, you should be able to fit your hand through the opening. Otherwise you may have to get your hands on some tweezers or chopsticks to assist.
The other consideration you may want to keep in mind is whether you’re making an open or closed terrarium. That’s going to affect what types of plants will be suitable for your terrarium.
If your container is going to be completely sealed (a closed terrarium), that’s going to be best for tropical, high humidity, low light loving plants. It’s also going to be less maintenance and require less watering. Open terrariums will be more suitable for plants that prefer dry, arid conditions. They also tend to be less prone to problems with mold growth and rot due to overwatering.
Here’s a simpler way to think about it: if you want to grow moss, choose a closed terrarium. If you want to grow succulents or cacti, choose an open terrarium.
For more info about the differences between opened and closed terrariums, check out this article.
Gather some rocks for the drainage layer
Get some small rocks or pebbles and add them to your container. It should go up to about one or two inches high. You can get some rocks either out in nature, or purchase some landscaping rocks from Home Depot.
If you’re building an open terrarium or are working with a thin, narrow container, you may want to make it a little bit deeper at 2-3 inches high.
You can also include some activated charcoal to purify water as it flows into the drainage layer and reduce odors. But that’s completely optional.
This layer of rocks and pebbles is going to provide a drainage layer for your terrarium. The purpose of the drainage layer is to allow water to drain out from the substrate and away from your plant roots. That’s going to help minimize the chance of developing root rot and mold growth.
The drainage layer also gives you a bigger margin of error when watering your terrarium. Terrariums can be sensitive to overwatering, but the drainage layer allows excess water to flow away from your plants rather than staying stagnant and allowing mold to grow.
Proper drainage is also going to aerate the soil, allowing your plant roots access to oxygen and nutrients in the soil. This is a natural phenomenon that happens with plants in the wild, where rainwater drains from the soil due to the pull of gravity.
You don’t necessarily have to be limited to rocks and pebbles for the drainage layer. You also have other options you can choose from including sand, egg crate, filter floss, or hydroton. Activated carbon is another option if you want to filter out any toxins and chemicals from your terrarium water.
For more info about the drainage layer, check out this article.
Cut out a separation layer material to cover the drainage layer
Grab either a Ziploc bag or synthetic wire mesh and cut out a section slightly larger than the size of your terrarium. An easy way to do this is to place your container above your material and use the container as a cutting guide.
If you’re working with something that doesn’t have holes already (like a Ziploc bag), you will need to poke some holes with a toothpick to allow water to pass through when it gets added to the terrarium.
Once you have that piece cut out, place it into your terrarium above your drainage layer. If you can, curve the edges upwards along the wall. That’s going to prevent plant roots from bypassing the separation layer by reaching through the sides of the container into the drainage layer.
The purpose of the separation material is to prevent your substrate from falling into the drainage layer and stop plant roots from growing into any stagnant water. It’s essentially a barrier that keeps the substrate out of the drainage layer.
The choice of separation layer material isn’t so important as long as it does the job and doesn’t degrade in water. Synthetic material like plastic is perfect for that. Metal is probably not a good choice because of rust, with the exception of rust-resistant aluminum.
The low budget option is to use some piece of plastic like a Ziploc bag that you have already available at home or in your recycling bin. That’s what I did for my first terrarium. If you want to do something that seems a little bit more professional, my recommendation is synthetic window screen mesh.
The separation layer should have small openings to allow water to pass through. At the same time, those openings should be so big that plant roots can grow through the openings. As a rule of thumb, just think about roughly the size of a window screen mesh as the upper limit on the hole size.
Fill in your substrate
Once you have your separation material in place, now you can add your soil or potting mix to the container. Depending on the size of your plants and the height of your terrarium, I recommend putting in about two or three inches for the substrate layer. A funnel or a roll of paper would be helpful for this step.
If your plants are on the larger side, you will probably want to make it a little bit deeper to make sure the roots have enough space to grow. At the same time, you don’t want to make the substrate layer too thick to give your plants enough space to grow above the substrate without running into the container.
The substrate layer is essentially what your plants are going to grow in. Potting mix is the go-to option for most terrariums, although that is by no means the only option you have.
If you wanted to go completely natural, you could gather some native soil from your backyard or from a local park. Just be aware that there may be bacteria or pests hitching a ride in the soil. You can always sterilize the soil by baking at 350° F for about 15 minutes to make sure it’s completely clean for your terrarium.
You can also consider using coir (coconut husks) or sphagnum moss. As long as it has sufficient nutrients to sustain your plants and retains moisture somewhat, it should work for your terrarium. You can always double check your particular plant species’ preference with a quick google search if you’re unsure.
Add your plants
Once your soil is in place, you are ready to start adding your plants. If you can, try to envision what you want your terrarium to look like as the final product. Think about your plants’ heights, shapes, and how you may want to shape the substrate for dips and hills.
If your container has a very narrow opening, you may need some chopsticks or some tweezers to help you out. Otherwise, you can just work with your hands for this part.
If your plants have any roots, you can also give the roots a quick trim to slow down the plants’ growth so that they will fit in your terrarium long-term. When you are ready, dig a little opening in the substrate for your plant and place it in. Cover up the hole/the root with substrate material once you have your plant in and you are good to go.
If you want to plant any moss, try to place them on the same substrate that you found it growing on when you harvested it. For example, if you saw the moss growing on a rock, try to place it back onto a rock in your terrarium. This will help ensure that the conditions mimic its natural environment as closely as possible to maximize your chances of success.
If you’re at a complete loss for what plants to add to your terrarium, here’s a quick list of common plants you can consider:
- Ficus Pumila (Creeping Fig)
- Hypoestes Phyllostachia (Polka Dot Plant)
- Bergenia Cordifolia
- Isotama Fluviatilis (Blue Star Creeper Plant)
For more ideas and recommendations, check out my list of recommended terrarium plants.
While it might seem tempting to throw in whatever plants you want into a terrarium, you may want to consider how well the terrarium matches your plants natural environment. This might take a quick Google search on your end.
I have some more info about that in this post.
If you are building a closed terrarium, you will want to lean towards plants that prefer high humidity, indirect light conditions. Moss and ferns are great choices for that.
An open terrarium on the other hand will be better suited for plants that enjoy dry, arid conditions. If you want to grow succulents, an open terrarium is a must-have requirement because of their sensitivity to excessive moisture.
Terrarium maintenance and care
Once you have your plants in your terrarium, you’re pretty much all set. The only thing that’s left to do is occasional maintenance.
For a few days, you will want to observe the condensation levels in the container. If you see condensation in the container all day 24/7, there’s probably too much water in the terrarium. You can also verify this by feeling the soil to see if it feels very soggy. In this case, you will want to open up the terrarium and let it air out for a day or two to reduce the water levels.
If you don’t see any condensation at all, you can probably add a little bit more water into the terrarium. Just be careful not to overdo it.
Preferably, you will want to use distilled water or rain water to water your terrarium. Tap water might be fine, but it’s possible there could be small traces of chlorine or lead in the water that might not sit so well with your plants.
In a closed terrarium, once you get the water levels right, you shouldn’t have to adjust the water levels much after that. At most, you may need to adjust it once every one or two months. You might even be able to get away with not adjusting the water levels at all for months or years.
An open terrarium, on the other hand, will need to be watered more frequently because water will evaporate over time. Just a very small amount of water every few weeks should be sufficient for your plants, especially if they prefer dry, arid conditions.
In the short-term, watering is the only maintenance item that you will need to be concerned with. Long-term, you may want to check in on your terrarium occasionally to make sure there’s no mold growth. If the water levels are correct, most likely you won’t run into mold problems. But even if you do, it should solve itself once you reduce the water levels a bit.
After a few months or a few years, you might need to revisit and start pruning your plants if they grow a little bit too large for your container. You can also remove any dead plants or leaf litter that builds up in your terrarium to keep your terrarium looking fresh.
Of course, if you don’t want to do any maintenance at all, that’s also an option. The oldest terrarium in the world is about 5 decades old and has only been opened once since it was planted. With no maintenance at all, it seems to be doing great so far.
If you’ve been following so far, that’s pretty much all you need to do to make a terrarium. But if you want to go above and beyond making a basic terrarium, there’s a few things that you can do to spice things up.
The first thing that comes to mind is adding some decorative items to your terrarium. There are all sorts of different ideas out there to turn your terrarium from a jar of plants to a tiny little world in a bottle.
Some of these items include (but are not limited to):
- Pine cones
These decorative items are where you can get really creative. Stones can be used as low mountains and figurines can be used as habitants of your tiny world. Your imagination’s the limit when it comes to how you can decorate your terrarium.
If you want to learn more about what you can do to decorate your terrarium, check out this article.
Besides decoration, there’s also a few other things you can add to your terrarium to enhance its livelihood.
Probably the most impactful piece you can add to your terrarium is springtails (and isopods will also work). Springtails are small, whitish gray insects that love feeding on mold and decaying organic matter. Basically the stuff that you don’t want to have in your terrarium. You can think about these guys as tiny janitors that live in your terrarium.
Springtails are found living in the soil, especially in moist, damp areas. The conditions inside of a terrarium create a little paradise for springtails.
If you want to add springtails to your terrarium, my recommendation is to buy a springtail starter kit online and address springtails in to your terrarium from the kit. The other option you have is to create your own springtail trap and catch some springtails yourself.
If you want to make a springtail trap, check out my detailed guide on how to catch springtails.
The other optional component that I mentioned briefly is activated charcoal. Activated charcoal is a way to purify water and air from toxins and odors as it passes through into the drainage layer.
You can use activated charcoal as the drainage layer itself or as an addition on top of the drainage layer. From my own research, I found that activated charcoal isn’t entirely necessary, and it may lose its effectiveness in the long run. But it can be helpful if you want the absolute best of the best for your terrarium.
If you are going to go this route, you can use activated carbon, horticultural charcoal, or activated charcoal. But do not use bbq briquettes as they have harmful chemical additives included and won’t go great with your plants.
How much does a terrarium cost?
If you add up all the components that you’ll need for a terrarium, the price should come out to about $30 from my analysis of the data.
But don’t let the price tag deter you from building a terrarium. Most of the materials you can get for free or you already have at home.
In fact, if you build a terrarium from native plants and materials, it won’t cost you a dime. All it takes is a little resourcefulness and a hike or two to gather all the materials that you need for a terrarium. If you follow my checklist that I linked to at the start of this article, you can build a terrarium completely free of charge.
Moss is a great plant that you can harvest with very little effort from your own backyard. You’ll even find moss growing in the cracks of the sidewalk. Just keep your eyes peeled and you’ll find plenty of opportunities to pick up plants to add to your terrarium without having to buy any plants.
So that’s all you need to know to start building a terrarium. Feel free to let me know how that went for you in the comments. Check out some of the related articles below if you want to learn more.