Terrarium Plants and How to Use Them

One of the big gardening trends at the moment is terrariums and that means terrarium plants. It’s easy to see why. They don’t take up much space; even people without as much as a window box can have a glorious mini garden. They also can look very stylish and yet require minimal care.

So when I was given a terrarium kit by my youngest, Henry, for Christmas, I quickly put down the Quality Street and started reading up on terrarium plants and how to plant them.

Here’s what I discovered.

What Makes Good Terrarium Plants?

A terrarium is a bit like a miniature garden contained inside a glass, often sealable container. If the container remains closed, the confined nature of the space means you are creating a tropical like climate – warm and humid. And without a lot of light. So the ideal plants for a closed terrarium are those that are compact but thrive in a moist environment, with indirect light.

If it isn’t closed, you won’t have the humid climate, but the space is still confined and light potentially restricted. And it’s also worth bearing in mind that in many terrariums, access is tricky. This means plants which require minimal care and don’t grow too fast will be your best bet!

Plants for Closed Terrariums

In theory a closed terrarium can last for years. That’s because you are creating a self-sustaining ecosystem. The warmth from the sun means moisture from the plants evaporates. This condenses on the sides of the container, and runs down the walls back into the soil. Equally while the soil provides initial food to get things going, longer term, debris from the plants as leaves rot, provide ongoing nutrients for the plants.

While this is the theory, and there are examples of terrariums which have survived decades without human interference, my hunch is that it’s probably quite a hit and miss affair. After all, the environment in the glass container can warm up pretty radically if it’s in too much sun. Furthermore, some plants may romp away too much and start dominating things. Other plants may get too humid and rot.

So to give your closed terrarium the best chance of success, you at least want to start out with some plants which work well in such a closed environment. A space with minimal airflow.

My son gave me a terrarium with a cork lid. So I can keep it closed if I want or have it open. I’m still not sure which way I’ll go with it, I’ll probably panic that the whole thing is overheating when it mists up and will chicken out and lift the lid!

But I want to have the option to keep it closed. So I first explored terrarium plants for a closed environment. From my research the consensus seems to be that good, safe options are:

• Ferns
• Moss
• Ivy
• Fittonia
• Syngonium
• Chamaedorea elegans (Parlour Palm)
• Begonia
• African violet
• Asparagus Fern

Let’s look at a few of these…

Begonia

I was really interested to see that Begonias are so good for closed terrariums. But then again, I guess it makes sense. After all, begonias are tropical plants that thrive in humid environments.

Beyond them being perfectly suited to the environment, the beauty of choosing a Begonia as one of your closed terrarium plants is that they come in a wide variety of colours and sizes. At my garden centre a sweet little variety called Begonia foliage rex caught my eye. But you can get some with variegated leaves, and so forth. I guess the major thing is to check it won’t get too big.

Fittonia

Like the Begonia, the Fittonia (Nerve Plant) loves the high humidity and moderate light conditions of a closed terrarium. Handily it’s compact too, so won’t outgrow its space too quickly.

Although the most popular vein colour is silvery-white, you can also readily find varieties with veins in red, pink, white, and green. So you can create an array of looks with Fittonia and it will work brilliantly with all sorts of other plants.

Ferns

I’m an absolute sucker for ferns. I have loads of them in the woodland style area of my garden but they’re mostly huge. So knowing I could have a dainty little variety in a terrarium intrigued me. The tiny, frilly leaved Nephrolepis called Fluffy Ruffles absolutely won me over. I also love Asplenium antigum below.

African Violets

African Violets come from the misty, high-altitude jungles of Tanzania and Kenya. So they bloom and grow better in moist air, something a closed terrarium has in abundance. However, if you are going to put an African Violet in a terrarium, choose a small variety and make sure your plant’s leaves can’t touch the walls. As all that moisture running down the walls, will create mould on the leaves it touches and run down them, like a funnel, and collect at the centre of the plant, rotting it.

Now, a quick caveat here. I’ve read some people saying they haven’t found African Violets very easy to grow in a closed terrarium as they need more air flowing around them. So I’d be tempted to have one in a container which has an easily removed lid, so you can let a bit of air in every now and then.

Syngonium

A Syngonium is quite an ordinary, almost bog-standard houseplant. But in a terrarium I feel it becomes elevated to something a bit more special. I think that’s because its large leaves catch the eye as its greenery thickens over time. Syngoniums are a great plant to use in a terrarium because they grow upwards rather than out – they don’t bully other plants in the confined space. I’ve read that they’re happy in both closed and open terrariums – so are top terrarium plants in my book.

Chlorophytum(Spider Plant)

Confession time…I hate spider plants. I think it’s because I associate them with all those endless baby spider plants you end up with and which no one wants. However, I believe they’re pretty good closed terrarium plants and this variety (laxum) has lovely contrasty leaves with a white stripe around the edge of lush green leaves.

Terrarium Plants with Height – Parlour Palm

Looking at the most effectively planted terrariums, you want to have one plant which gives things a bit of height. That’s where a very small Parlour Palm (Chamaedorea elegans) comes in. It’s very easy to care for (the dream as far as I’m concerned) and it looks a bit like a mini tree when used in a terrarium.

Terrarium Plants with Height – Asparagus Fern

A bit like the Parlour Palm, the Asparagus Fern has a tree like structure, but it looks much softer. I think this makes it an elegant choice for a terrarium. An Asparagus Fern looks very lovely on its own, as quite a statement plant – or in combination with lower growing plants. Furthermore, with its love of humidity it’s fine in a closed terrarium.

Open Terrarium Plants

An open terrarium has none of the humidity of its closed counterpart. In fact, it’s essentially a differently shaped plant pot! However, with its high sides and limited access, it may be tricky to water (or get at) whatever is in the terrarium. That’s why cacti and succulents – desert plants that thrive in dry conditions, are slow (and low) growing and don’t need a lot of TLC are good for open terrariums.

• Air plants
• Cacti
• Haworthia
• Crassula Ovata

Cacti

Cacti are not plants for the impatient. They’re very slow-growing. But this means they’re brilliant for terrariums as they won’t crowd out the space quickly. If you are going to use them, you could have them on their own, or maybe combine with them with succulents. Just make sure your terrarium has a large opening as they cannot bear a humid environment. They need plenty of air flow.

Air Plants

If you can access your terrarium and are a beginner, you could consider an air plant. Air plants don’t need soil. They extract moisture and nutrients from the air. So you can simply pop an air plant in a terrarium on its own or put on a stone, pebbles or a bit of wood. You will need to remove the air plant once a week to water it by misting it or dunking it into a bowl of water, but that’s about it!

Haworthia

Haworthias are such handsome plants and could combine well with a cactus in a terrarium as they need minimal watering. You can get them in lots of shapes and colours. For instance there’s the zebra-like, stripey beauty Haworthia fasciata or Haworthia cooperi, which has delectable, white and green tear- shaped leaves. Whichever one you go for, as long as your terrarium gets bright but indirect light, and your plants will be very happy.

Crassula Ovata

Crassula Ovata (Jade plants) are popular choices for open terrariums as they can make quite a statement. You can even shape them like a miniature tree if you are skilled in the art of Bonsai (I’m not). But a word of warning they like frequent watering, so don’t combine them with cacti as the poor old cacti won’t thrive.

How to Use Your Terrarium Plants

In terms of how you plant up your terrarium, my advice is based on the kit which I received for Christmas.

What you Need To Create a Terrarium

• Container
• Clay balls or stones or pebbles for drainage
• Potting soil
• Activated charcoal
• Flat layer of moss
• Plants
• Optional – other decorative bits (larger stones, bits of wood)

Firstly you need a container. This could be a glass vase, a pasta jar, a preserving jar, a fish bowl…you name it. It can be closed or open. Just choose your terrarium plants based on which route you are going for.

In essence you put a deepish layer of clay balls (or you could use stones or pebbles from your driveway) in the base of your terrarium; these will provide the drainage.

You then sprinkle a little activated charcoal over this base.

You can get the charcoal from most garden centres or online. It essentially helps neutralise any odours from your terrarium.

If you have any moss (you could scrape it from your lawn) put this on top of the drainage stones. This will stop the soil dropping through.

Next add a layer of soil. It needs to be generous enough to host your plants’ roots nice and deep. Then you can do the fun bit and add the plants. If the opening of your terrarium is limited you may need to use special, narrow, long handled tools to do the planting. My kit came with some, but to be honest I think chopsticks could work as well.

Try to avoid your plants touching the walls of the terrarium so they have room to grow, but other than that, do whatever you fancy. After the plants you can add finishing touches such as larger stones, sand, moss or gravel to cover the soil.

Time to Play with those Terrarium Plants!

Having planted up my own terrarium, I can quite easily see how creating this gorgeous mini world could be quite addictive. As having done a closed one, I’m now itching to create an open one with succulents and cacti…just something simple, with perhaps a sculptural piece of driftwood, like the one below. (Though I don’t like the funny shiny stones they’ve used).

Then again there are so many other styles I fancy creating. For instance, a circular open container would be fab.

I’d also like to have a go at creating a tall, tree-like effect with ferns.

Lastly, as a fern and moss lover, this one below is my absolute favourite. I have to have a go at creating a mossy secret paradise like this. (I knew all that moss on my lawn would come in handy!)