Choosing a terrarium container

How to Choose the Right DIY Terrarium Containers

There are so many potential terrarium containers, the choice is almost overwhelming. Do I want it square or round, big or small, glass or plastic? And so on.

After all, pretty much anything fully transparent can function as a terrarium container. But does that mean all terrarium containers are equal? Not by a long shot. 

Some are challenging to build with, and others simply aren’t shaped for proper plant support. 

Read on to find out what to look for when finding the perfect terrarium container for your home!

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Terrarium Shapes & Sizes

Terrariums really do run in all shapes and sizes.

Though if you run a Google image search for the word “terrarium” there’s a good chance half the photos that pop up will be geometric. Contrary to what Urban Outfitters might suggest, there are more to terrariums than the copper pyramid. 

The truth is that technically, any glass container capable of holding the necessary components of a terrarium will work. All the weird and wonderful shaped vessels in the world are potential terrarium containers.

As you go on your hunt for your terrarium container of choice, here are a few things to consider.

1. The Size of the Container

There’s no maximum size for a terrarium – the sky’s the limit – but there’s definitely a minimum size for a fully functioning terrarium. Teeny tiny terrariums are a thing, but they tend to be just a little bit of moss or a single small plant. Not a full ecosystem.

The size of the container will obviously be dictated by where it’s going in your house, but I’d definitely recommend going as big as you can.

Not just because bigger is generally better, but it’s actually better to give your plants more space. It’s recommended to be able to give the plants at least ⅓ of the terrarium as free space.

You’ve more freedom with a bigger container too. More space for plants, more decorations, interesting features and creative elements.

2. The Shape of the Container

You can get super creative with terrarium shapes (hell, it’s part of the fun!) but it’s important to remember that you still need a strong foundation and enough space for plants.

Containers with a uniform shape (e.g. a box or cylinder) or a broad curve (e.g. a globe) tend to provide a consistent shape, so everything is nice and proportional.

Whereas something with a narrow base may not provide enough drainage, or enough substrate for the plants to thrive.

It’s just something you’ll have to eyeball at the time.

3. The Size of the Opening

Experienced terrarium builders can like a challenge, and sometimes opt for containers with a very narrow opening.

Just like building a ship in a bottle.. well you can build terrariums in bottles. The likes of the demijohn terrarium are quite classic too, but still involve planting through a very narrow opening.

If you’re just getting started with terrariums, I’d recommend going for a container with a nice wide opening to give you lots of space to manoeuvre. It can be super frustrating to try to plant effectively when you can barely fit your terrarium tools in.

Cylindrical terrarium container
Here’s one I made earlier; large, uniform and with a wide opening

Terrarium Container Materials

Terrariums tend to be made from just a few select materials, as they need to be robust, non-reactive and fully transparent. That basically just leaves us glass and plastic.

They need to be fully transparent so we can see the plants (that’s the point after all) but also because plants need sunlight for photosynthesis. To be more specific, plants use the visible spectrum of light for photosynthesis.

Except for green, which they reflect – which is why they appear green to us.

Glass Terrarium Containers

Glass terrariums are the most common kind and the ones I’d recommend.

They’re great for all of the above practical reasons, but also because terrariums are ornaments too. And frankly, aesthetics count in this department. If I’ve created a beautiful plant ecosystem to display, I want it housed in an equally beautiful container.

*One thing to note, coloured glass filters out parts of the visible spectrum, so can reduce the amount of light your plants receive. Plus, you won’t be able to see them so well.

Common Types of Glass Terrarium Containers:

  1. Geometric glass terrariums
  2. Mason jar terrarium
  3. Wine bottle terrarium
  4. Wardian case terrarium
  5. Demijohn terrarium

Plastic Terrarium Containers

Plastic generally works fine for terrariums too, but I’d choose glass where possible.

If cost is an issue ( I can appreciate not everyone has $100 to fork out for a luxury glass terrarium) then upcycling a plastic container is always an option I support. But then you can always upcycle a glass bottle of wine too? A reason to buy more wine is always something I can get behind!

Though, depending on the type of plastic used, there’s a possibility of toxic compounds leaching into the terrarium environment too.

We’ve been warned by authorities not to leave plastic bottles in the sunlight due to leaching, surely a plastic terrarium full of water is going to leach chemicals if left for years?

Interestingly, this 2015 study found that BPA actually increased the growth rate of plants, but extra plant growth isn’t exactly desirable in terrariums. Plus the growth was correlated with high levels of stress hormone in the plants, so the actual health of the plants were adversely affected.

Where to Buy Terrarium Containers?

I swear, you can buy suitable terrarium containers from almost anywhere these days.

Of course, you can hop online to Etsy and very quickly find yourself a beautiful wardian case or geometric terrarium.

If you’re after a small terrarium, there are lots to choose from. Whereas choice is limited for larger terrariums.

Any homeware store is likely to stock some sort of glass vase or jar. In fact, if you love to hunt for a bargain, my favourite place to go is TK Maxx (TJ Maxx in the states). I regularly find gems in there along with other terrarium supplies.

Or, you could just buy a bottle of your favourite wine or bourbon and go from there… just saying.

Now, Over to You

Hopefully you’re feeling better equipped to pick the right terrarium container for you and your home.

Sure, there are a few things to consider, but don’t overthink it and get bogged down. Generally if you get a large(ish) glass container that’s square or round – it’ll work!

Getting the right container is just the beginning, then the real fun starts.

Have you already picked your terrarium container? Let me know what you went with in the comments!

2 thoughts on “How to Choose the Right DIY Terrarium Containers”

  1. I have found some really great glass containers for terrariums at local thrift shops and want to sterilize them before use. Is this necessary and if yes, what is the best way to do this to kill any germs but not harm future plants? (same question for used flower pots)

    1. Hey Michael, yeah it’s always a good idea to clean down any new glass terrarium containers. Wiping down with isopropyl alcohol works to sterilise it, then you can finish with a microfiber cloth to remove any remaining debris.

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