It’s no secret that I’m obsessed with making terrariums. These closed containers are high in humidity, enabling the growth of a fascinating range of plants and mosses and this gives me an immeasurable amount of joy. I wish I could tell you a more romantic story about how I discovered horticulture and was destined to be a botanist from a young age, but in reality my love of plants began when I was 23 and I got a job in the reception class of a primary school. I worked one-to-one with a four-year old and we were put in charge of the class composting system, which I then became obsessed with and ended up researching deeply. I soon realised I wouldn’t see the banana skins and apple cores actually turn into compost within the academic year, but through my research I discovered vegetable gardening and right next to the school was an allotment site with vacant plots. I put my name on the waiting list and within two weeks I had one sixteenth of an acre of land to grow vegetables on. The allotment was my gateway into the world of plants and from there, any plans I made seem to centre around visiting horticultural places. I went to countless arboretums and botanical gardens and during a trip to India, made a detour to see a 140-year old Wisteria chinensis in Darjeeling.
In 2016, I was in a local garden centre and spotted a large, bulbous and hideous bonsai in the reduced section. The label read ‘Ficus ginseng’. I knew nothing about bonsai but for £10 I thought why not? I took the bonsai home and watched it slowly drop its leaves, one by one, until it was a bare bulbous trunk in a water-stained pot. Much like vegetable gardening, I took a deep dive into bonsai and bought many books on the subject, reading them cover to cover. Bonsai isn’t a hobby anyone usually picks up quickly; it's more of an art form that people dedicate their lives to. Being a total novice who was keen to learn, I got in touch with those highest in the field and was fortunate enough to spend three days with Peter Chan of Herons Bonsai and had one-to-one sessions with Harry Harrington of Bonsai4me. Bonsai isn’t a huge part of my life anymore but it was during this period that I really learned about the fundamentals of horticulture.
I don’t recall exactly how I discovered terrarium building but I remember making one of my first terrariums with an IKEA vase and a Fittonia—it quickly perished and most of my other attempts ended in the same way.
I know now that the guides I followed contained bad advice and uninformed clichés that were counterproductive when it came to the longevity of a terrarium. One of the fundamentals of bonsai is to use the correct substrate and if the creator doesn’t follow this rule then the tree will ultimately fail, usually swiftly. I applied the use of bonsai mediums to a few terrariums and they almost immediately looked happier and healthier. It was here that I discovered a key component to terrarium health lies in
the substrate. I continued making terrariums as a hobby and started selling them in September 2019, alongside my full time job. I regularly posted on social media, educating people on how they could make their own terrariums, as well as tracking my own journey. Things were going well until the world went into lockdown in March 2020 and while this paused the cashflow, it turned out to be the best thing that could
have happened to my business.
During the lockdown period I dedicated my time to creating content on Instagram, quickly building up a substantial following before diving into YouTube in mid 2021 where I could make longer form, more educational videos. In late 2021 I started a TikTok account and this was when my social media channels exploded. I uploaded a video of some snails, woodlice and millipedes eating a slice of cucumber in a large bioactive terrarium and it blew up, gaining 66 million views to date. Since then my videos have been viewed hundreds of millions of times, which has lead to me displaying at the RHS Chelsea Flower Show where I won a gold medal, working with Great Ormond Street Hospital and being featured numerous times in local and national news articles. Most recently, I’m delighted to say I’ve signed a contract with the literary, film and TV agency, Own It!
An interesting aspect of terrarium building, and one that really helped my social channels grow, is the inclusion of small animals. Creatures like woodlice, springtails, millipedes and even tiny garlic snails (Oxychilus alliarius), that grow no bigger than the nail on your pinky finger, have an active role in the ecosystem. Woodlice and millipedes process plant matter and turn it into waste, which helps enrich the substrate and aids plant growth. Springtails act as the caretakers of the terrarium by feeding on mould and decaying matter, preventing small outbreaks from becoming large ones. The snails, I must admit, do have a habit of chewing on the leaves of certain plants so it's important to be selective around plant choice.
It’s not necessary to add small creatures to your terrariums but it does create another level of interest that resonates with a wider audience. I recently did a series of talks and demos for Great Ormond Street Hospital as part of their involvement in the Bloomsbury Festival and it was clear to see that while the audience were interested in the plants and terrariums, the arthropods, hexapods and insects created a higher level of fascination. This is also reflected in my social channels where the posts about ‘bugs’ get higher views. As a plantsperson this was initially frustrating but I’ve come to accept that the creatures are as much of a part of the terrarium as the plants.
If you’re keen to make your own terrarium then I believe there are three important things to get right.
Substrate
The main body of my substrate consists of coir, worm castings and one or more of the bonsai mediums: moler clay, akadama, zeolite, lava rock, hydroleca or propagating bark. This can be supplemented further by adding composted bark, leafmould or leaf litter. The aim is to create a medium that is water retentive, well draining and nutritious. The bonsai mediums wick up water but also create small air pockets in the coir which keeps the medium aerobic. I highly advise against the use of compost or topsoil as this is far too water retentive and can quickly lead to the demise of your terrarium. There are high quality mixes available from reputable suppliers such as Soil Ninja or Grow Tropicals if you’re in the UK.
Light
It seems obvious but providing your terrarium with sufficient light is fundamental to it surviving. The perfect spot in your living room, aesthetically speaking, is often a poor choice for plants to grow. Natural light is the best choice but it’s also tricky to navigate; in the UK north-facing windows are a good choice as they get no direct sun, but during the winter they become cold traps that will inhibit the growth of the tropical plants. A good rule of thumb is to allow the plants to see as much of the sky as possible without sitting in the sun. Alternatively, the use of artificial lighting is often the best choice for many homes. There is no need for expensive grow lights; warm, cool or daylight white LED bulbs work just fine so long as they’re close enough to the plants. To remove any ambiguity around how much light is needed I recommend using a light meter. A minimum of 1076 lx (100 fc) is advised. Remember, many terrarium plants come from the understory or forest floor level of the rainforest and won’t like to be blasted by the sun.
Watering
There are no drainage holes in a terrarium so watering correctly is important. Deionised, distilled, rain or reverse osmosis water is best but filtered is an adequate alternative. Carefully water thoroughly during the construction of the terrarium and water sparingly going forwards. Rather than watering to a schedule, learn to observe the substrate and feel the weight of the terrarium. Is the substrate dark in colour? Does the terrarium feel heavy? The chances are it doesn’t need more water. Is it light in colour? Does it feel light? It probably needs a spray. The age old test of sticking your finger into the substrate is pretty fool proof, provided you can get your hand into the terrarium. As a general rule, the substrate should be slightly moist.
This article wouldn’t be complete without a mention of plants, so here are five of my favourite terrarium plants (including three types of fern).
Pyrrosia nummularifolia (Creeping Button Fern)
An epiphytic micro fern species from Indonesia and Papua New Guinea that also grows well terrestrially. Once established it’ll cover the floor or background of a terrarium with beautiful oblong shaped leaves. It’s easy to propagate by taking cuttings and roots directly in a terrarium or on sphagnum moss. It needs warm temperatures and high humidity to flourish. Suitable for small and large terrariums.
Nephrolepis exaltata ‘Marisa’ (Sword Fern)
A beautiful fern with dense masses of lacy light-green leaves. In ideal conditions it has a habit of growing tall and spreading out wide so is best used in larger terrariums as a background plant. It can be divided by splitting the rootball and omits a sweet aroma when the fronds are disturbed. Ensure the plant doesn’t sit in the cold (nothing under 12 °C) and has high humidity. I have successfully grown this fern as a house plant.
Pteris quadriaurita ‘Tricolor’ (Tricolour Fern)
Like the name suggests, the leaves of this tender tropical fern cycle through colours of bronze, red and green as it matures. It prefers a bright spot and can grow quite large but by pinching out the older leaves it can be kept smaller. Ensure the substrate is well draining and doesn’t dry out. Suitable for medium to large terrariums.
Ficus pumila ‘Quercifolia’ (Oak Leaf Fig)
Probably the quintessential terrarium plant. Slow growing with tiny oak-shaped leaves, it needs consistently damp substrate and under good light the growth is compact and the leaves stay small. Under lower light, the leaves get much larger and the spacing
between nodes elongates. It takes to cuttings well and is suitable for terrariums of all sizes.
Peperomia rotundifolia (syn. P. prostrata, String of Turtles)
Epiphytic in nature, there’s no wonder this plant never thrives in the water retentive compost it's sold in. Take rootless cuttings and place on top of moss or directly on good quality terrarium substrate and within a few weeks it’ll have pushed out substantial roots. P. rotundifolia really thrives in high humidity and good light; the leaves plump up and it pushes out new growth quickly in ideal conditions.
BEN NEWELL
Ben is a content creator, influencer, public speaker, owner of Worcester Terrariums and Chelsea Flower Show Gold Medalist. He has established himself as a leading figure in the field of terrarium building, amassing a total of 1.5 million followers across his social platforms. Ben’s work centres around the creation of micro ecosystems called terrariums and he has become well known for his short form video content, with his videos totalling up hundreds of millions of views. He has been nominated for the Garden Media Guild Social Media Communicator of the year award 2022 and has been featured in numerous local and national news articles as well as Encyclopaedia Britannica in their ‘Terrarium Guide For The Absolute Beginner’ article. Ben has created a series of videos for social media giants Buzzfeed and has been featured multiple times on UNILAD and LADbible’s pages.
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