How To Build A Mushroom Terrarium

You can build a mushroom terrarium with just a few simple supplies and a little patience, and it’s one of the most rewarding little projects you’ll ever tackle.

Building a mushroom terrarium is totally doable at home, and it doesn’t require a green thumb or expensive gear.

Whether you’re a seasoned plant parent or a total beginner, creating a mushroom terrarium brings a magical, woodland vibe right onto your desk or windowsill.

In this post, we’ll walk through why you’ll love building a mushroom terrarium, the best mushrooms for this setup, the exact steps to build a mushroom terrarium, and how to keep it thriving.

Let’s dig in.

Why Build A Mushroom Terrarium?

There are plenty of reasons to build a mushroom terrarium, and once you see one, you’ll understand the appeal.

A mushroom terrarium is essentially a miniature ecosystem where mushrooms grow in a controlled, glass-enclosed environment.

The main reason people build a mushroom terrarium is the sheer visual charm—tiny caps popping up from mossy soil looks like something out of a fairy tale.

But it’s not just about looks.

When you build a mushroom terrarium, you’re creating a self-sustaining microclimate that holds humidity perfectly, which is exactly what mushrooms love.

Unlike regular potted plants, a mushroom terrarium requires very little maintenance once it’s set up.

Plus, it’s a fantastic educational project for kids or anyone curious about fungal growth.

And honestly, there’s nothing quite like watching your mushroom terrarium come to life over a few weeks.

What You Need Before You Build A Mushroom Terrarium

Before you build a mushroom terrarium, you need to gather a few key components, all of which are easy to find.

Here’s what you’ll need:

1. A Glass Container

The best container to build a mushroom terrarium in is a wide-mouth glass jar, a fishbowl, or a repurposed cookie jar.

Avoid containers with narrow necks because you’ll struggle to arrange the layers inside.

Make sure your container has a lid, or you can cover it with a piece of glass or plastic wrap.

If you don’t have a lid, you can still build a mushroom terrarium, but you’ll need to mist it more often to keep humidity high.

2. A Substrate Base

To build a mushroom terrarium, you’ll need a substrate that mimics the forest floor.

The most common choices are sphagnum moss, coconut coir, or a mix of peat and vermiculite.

This layer sits at the bottom and holds moisture while giving your mushrooms a stable foundation.

You can also add a handful of organic potting soil if you want a richer base.

3. Mushroom Spawn or a Grow Kit

This is the star of the show when you build a mushroom terrarium.

You can buy mushroom spawn online—it’s basically mycelium that’s ready to colonize your substrate.

Even easier, you can buy a small mushroom grow kit and simply crumble the colonized substrate into your terrarium.

The best mushrooms for a mushroom terrarium are small, humidity-loving varieties.

Best Mushrooms For A Mushroom Terrarium

Not every mushroom will thrive in a terrarium, so choosing the right species matters.

Here are the top picks when you build a mushroom terrarium:

1. Oyster Mushrooms

Oyster mushrooms are the easiest choice for a mushroom terrarium because they’re aggressive colonizers.

They grow fast, tolerate a wide range of conditions, and produce beautiful, fan-shaped caps.

If this is your first time building a mushroom terrarium, oyster mushrooms are the safest bet.

2. Enoki Mushrooms

Enoki mushrooms love cold, humid environments, which makes them a perfect fit for a mushroom terrarium.

They grow in delicate clusters with long, thin stems and tiny caps.

Enoki adds a dreamy, almost ethereal look to your mushroom terrarium, and they’re surprisingly easy to care for.

3. Reishi Mushrooms

If you want something that looks like a sculpture, reishi mushrooms are awesome for a mushroom terrarium.

They produce glossy, reddish-brown shelves that look stunning against green moss.

Reishi grows a bit slower, but the payoff is worth it when you build a mushroom terrarium that looks like art.

Step-By-Step Guide To Build A Mushroom Terrarium

Now let’s get to the good stuff—the actual steps to build a mushroom terrarium.

Follow these instructions and you’ll have your own tiny fungal forest in no time.

Step 1: Clean and Sterilize Your Container

Before you build a mushroom terrarium, wash your glass container with hot, soapy water.

Rinse it thoroughly, then wipe the inside with rubbing alcohol.

This step is crucial because mold and bacteria can outcompete your mushroom mycelium if you skip it.

Let the container dry completely before moving on.

Step 2: Add a Drainage Layer

To build a mushroom terrarium that doesn’t get waterlogged, start with a thin layer of small pebbles or gravel.

Add about half an inch of pebbles at the bottom.

This gives excess water a place to pool, away from the roots of your mushrooms.

If you skip this step, your mushroom terrarium could become soggy and rot.

Step 3: Add Your Substrate

Now add your moistened substrate on top of the pebbles.

Aim for a layer that’s about two to three inches deep.

If your substrate feels dry, mist it lightly with water before you build the next layer.

You want it damp, like a wrung-out sponge, but not dripping.

Step 4: Introduce the Mushroom Spawn

This is the heart of building a mushroom terrarium.

Take your mushroom spawn and crumble it evenly over the substrate.

If you’re using a grow kit, break the colonized substrate apart and mix it gently into the top inch of your base.

Don’t bury the spawn too deep, or the mycelium will take forever to reach the surface.

A light mix is all you need when you build a mushroom terrarium.

Step 5: Add a Moss Topping

For that classic forest look, add a thin layer of live or preserved sphagnum moss on top of the spawn.

This not only looks gorgeous in your mushroom terrarium, but it also helps retain moisture.

Mist the moss lightly so it’s slightly damp.

The moss will also serve as a visual cue for when you need to water your mushroom terrarium.

Step 6: Mist and Cover

Give the entire setup a gentle mist with a spray bottle.

Then, cover your mushroom terrarium with its lid or a piece of glass.

The goal is to trap humidity inside.

You want the inside of the glass to look slightly foggy, but not streaming with condensation.

If it’s too wet, crack the lid open for a few hours each day.

Step 7: Provide Indirect Light and Wait

Place your mushroom terrarium in a spot with bright, indirect light.

Direct sunlight will cook your mushies, so keep them away from south-facing windows.

Now comes the patience part.

It can take anywhere from one to three weeks to see visible pins (tiny baby mushrooms) form.

When you build a mushroom terrarium, the hardest part is literally waiting for the magic to happen.

How To Care For Your Mushroom Terrarium

Once you’ve learned how to build a mushroom terrarium, the next step is keeping it alive.

Here are the essentials:

1. Maintain High Humidity

Mushrooms are about 90% water, so humidity is non-negotiable.

Check your mushroom terrarium daily and mist the moss whenever it looks dry.

If you see condensation on the glass, you’re in the perfect zone.

If it looks bone-dry, mist more thoroughly.

2. Provide Fresh Air Exchange

As important as humidity is, your mushroom terrarium also needs fresh air.

Open the lid for 10 to 15 minutes every day or every other day.

This prevents carbon dioxide from building up.

Without fresh air, your mushrooms might grow tall and leggy, and they can suffocate.

3. Keep Temperatures Steady

Most mushrooms prefer temperatures between 60°F and 75°F (15°C to 24°C).

Avoid placing your mushroom terrarium near heaters, air conditioners, or drafty windows.

Sudden temperature swings can stall growth or cause your mushrooms to abort.

4. Harvest and Reuse

When your mushrooms mature and their caps flatten out, they’re ready to harvest.

Twist them gently at the base to pull them off.

After your first flush, you can often get a second round from the same setup.

Just mist the substrate again and keep the lid on.

Many people who build a mushroom terrarium enjoy multiple harvests before the nutrients run out.

So, How Do You Build A Mushroom Terrarium?

You can build a mushroom terrarium by layering pebbles, substrate, and spawn in a glass container, then maintaining high humidity and indirect light.

It’s a simple project that yields stunning results.

When you build a mushroom terrarium, you’re not just growing a plant—you’re cultivating a living ecosystem that rewards you with constant surprises.

Now that you know exactly how to build a mushroom terrarium, it’s time to gather your supplies and give it a shot.

Your tiny forest is waiting, and you’ll be amazed at what you can grow in a glass jar.