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You can make a mushroom terrarium with just a few supplies, and it’s a surprisingly simple project once you understand what these fungi need to thrive.
Making a mushroom terrarium is all about recreating a humid, shaded, and nutrient-rich environment that mimics the forest floor where mushrooms naturally pop up.
If you’ve been wondering how to make a mushroom terrarium that actually grows and lasts, you’re in the right place because this guide covers the entire process step by step.
In this post, we’ll walk through choosing the right mushrooms, layering your terrarium properly, and maintaining the moisture levels that keep your mini mushroom world alive.
Let’s dig into the fun of building your own tiny fungal ecosystem.
Why Making a Mushroom Terrarium Is Totally Doable
Making a mushroom terrarium might sound like a science project, but it’s actually one of the most forgiving indoor gardening hobbies you can try.
The reason why making a mushroom terrarium works so well is that you’re essentially giving the fungus a closed, self-contained greenhouse.
Unlike outdoor gardening, you control the humidity, light, and airflow, which means mushrooms don’t have to compete with weeds or pests.
When you learn how to make a mushroom terrarium correctly, you can enjoy fresh mushrooms growing right on your desk or windowsill.
The best part is that you don’t need expensive equipment, just a jar or glass container, some substrate, and mushroom spawn.
1. Choose Mushroom Species That Love Terrariums
Before you start building, you need to pick the right kind of mushroom for your terrarium setup.
Oyster mushrooms are the easiest for beginners because they grow fast and tolerate a wide range of conditions.
Pink oyster mushrooms are especially popular in terrariums because they add a pop of color and don’t require much light.
Reishi mushrooms are another great choice, as they produce beautiful, woody-looking shelves that look stunning in a glass enclosure.
Avoid shiitake or portobello for your first mushroom terrarium because they need more specific temperature and airflow than a closed jar can provide.
When you’re ready to learn how to make a mushroom terrarium, just remember that the species you choose determines how much attention you’ll need to give it.
2. Pick the Right Container for Your Mushroom Terrarium
The container you choose plays a huge role in how well your mushroom terrarium retains humidity.
A wide-mouth mason jar is perfect for a small mushroom terrarium because it’s easy to clean and lets you see the mycelium spreading.
If you want a bigger display, you can use a glass cookie jar or even a small fish tank with a lid.
Make sure your container has a lid that can be opened slightly for fresh air exchange, because mushrooms need some oxygen to fruit properly.
A completely sealed terrarium will trap too much carbon dioxide, which can cause mushrooms to grow tall and spindly instead of forming nice caps.
So when you’re thinking about how to make a mushroom terrarium, start with a container that gives you both humidity control and a way to vent.
3. Layer the Substrate Like a Pro
The substrate is the “soil” that feeds your mushrooms, and getting this layer right is the secret to a thriving mushroom terrarium.
Start with a drainage layer of small pebbles or perlite at the bottom of your container to prevent water from pooling.
Next, add a thin layer of activated charcoal, which helps absorb odors and keeps the environment fresh inside your mushroom terrarium.
On top of that, add your main substrate, which can be a mix of coconut coir and vermiculite, or even sterilized straw.
Oyster mushrooms love straw-based substrates, while reishi prefer hardwood sawdust, so match the substrate to your chosen species.
Mix your mushroom spawn into the substrate evenly, then lightly mist the top with water until it’s moist but not soaking wet.
This layering technique is essential when you’re learning how to make a mushroom terrarium because it prevents rot while keeping moisture available.
Best Practices for Maintaining Your Mushroom Terrarium
Once you’ve assembled your mushroom terrarium, the real work is maintaining the right environment so your mushrooms actually fruit.
Many people think making a mushroom terrarium is a set-it-and-forget-it project, but that’s not quite true.
You’ll need to check your terrarium every day for the first week or two, especially while the mycelium is colonizing the substrate.
The good news is that the maintenance routine is simple, and it all comes down to three key factors.
1. Keep Humidity High Inside the Mushroom Terrarium
Mushrooms are about 90% water, so they absolutely need high humidity to develop properly.
Aim for around 85-95% humidity inside your mushroom terrarium, which you can achieve by misting the inside walls daily.
You’ll notice tiny water droplets forming on the glass, and that’s a perfect sign that your mushroom terrarium is at the right humidity level.
If the substrate starts looking dry or cracked, give it a quick spritz and close the lid to trap the moisture.
However, be careful not to over-mist because standing water will invite mold, which can outcompete your mushrooms inside the terrarium.
2. Provide Indirect Light, Not Direct Sun
Mushrooms don’t photosynthesize, so they don’t need direct sunlight, but they do use light as a signal to start fruiting.
Place your mushroom terrarium near a north-facing window or under a fluorescent light with a daylight bulb.
Direct sun can heat up the glass and cook the mycelium, so always keep your terrarium in a shaded spot.
If you’re making a mushroom terrarium in a room with no windows, a simple LED grow light works just fine.
Provide about 6-8 hours of indirect light per day, and you’ll notice mushroom pins starting to form within a couple of weeks.
3. Manage Fresh Air Exchange
Mushrooms need oxygen, and they produce carbon dioxide as they grow, so you have to open the lid regularly.
Once you see pins (tiny mushroom beginnings), open the lid for a few minutes twice a day to let in fresh air.
This sudden burst of oxygen actually encourages mushrooms to grow thicker stems and wider caps.
If you skip this step, your mushroom terrarium might produce long, skinny mushrooms that look like they’re stretching for air.
A quick daily fanning with the lid is all it takes to keep your fungal friends happy and healthy.
Troubleshooting Common Mushroom Terrarium Issues
Even when you follow the steps on how to make a mushroom terrarium, things can go wrong, but most problems are easy to fix.
The most common issue is green or black mold growing on the substrate, which usually means there’s too much moisture or poor air circulation.
If you spot mold, scoop it out carefully with a spoon and open the lid for a few hours to dry things out slightly.
Another issue is mushrooms turning yellow or mushy, which typically means they’ve gotten too much water sitting on them.
Cut back on misting and make sure your drainage layer is working properly so excess water has somewhere to go.
If your mushrooms just aren’t growing at all, check the temperature, because most edible mushrooms prefer a range between 60-75°F.
With a little patience and observation, you’ll get the hang of keeping your mushroom terrarium balanced.
So, How to Make a Mushroom Terrarium Successfully?
You can make a mushroom terrarium successfully by choosing easy species, layering the substrate properly, and maintaining high humidity with fresh air exchange.
Making a mushroom terrarium doesn’t have to be complicated, and as long as you mimic that damp, shady forest floor environment, your mushrooms will reward you.
The process of making a mushroom terrarium is also incredibly rewarding because you get to watch the mycelium spread and then see tiny mushrooms appear almost overnight.
Whether you’re growing oyster mushrooms on your kitchen counter or reishi in a glass jar, this hobby is equal parts science and art.
So gather your container, your substrate, and your mushroom spawn, and start making a mushroom terrarium today.
Soon enough, you’ll have a living, breathing miniature forest that’s as beautiful to look at as it is fun to maintain.