Moss. When most people think of moss, their eyes start to droop shut or their attention starts to wander. Understandable, because moss isn’t exactly the most exciting plant in the world, but it’s a very important part of a terrarium for any number of reasons. Rolling stone jokes aside (gotcha, we didn’t make one), moss is extremely useful for terrarium gardening both in terms of visual appeal and in terms of functionality.
Visually, it might seem a bit boring at first – and some of them are a bit boring. But some of them, like the moss pictured in the header image of this very website, begin to create tiny little stalks that contain spores, and provide an interesting visual contrast to the deep, rich green that characterises so many types of moss. Some are even more expressive, creating miniature flowers! The more you stop to think about it, though, the more you start to see the appeal of them. They grow slowly, they tend to like a great deal of humidity, and they don’t require a great deal of sunlight to thrive – they’re almost the perfect terrarium plant.
Not all mosses are created equal for the terrarium environment, though. It’s possible to buy moss online, but if you live anywhere near any kind of green space – whether you’re in a big city or a small town or a ranch out in the middle of nowhere – your best bet is often to go out and harvest some moss for yourself. The only thing to keep in mind is that some mosses will do better than others, and you don’t want to accidentally introduce any kind of mold or fungus into your terrarium! After you go moss harvesting, take a couple of weeks and place your collections in jars or containers of their own. Keep them humid, and see how well they do in a closed environment. Be sure to bring a fair amount of the soil they were naturally growing in, or else you may find their survival rate is much lower than you’d hope.
If you’re looking to create an extremely basic terrarium, you could use various kinds of mosses mixed with some interesting rocks, and see what kind of abstract design patterns you can create using nothing but moss. There are different textures and different colours, and each one is probably more interesting than you’d think at first, and especially so when you see them up close. Instead of just being a bland carpet, they’re actually some of the most basic plants on the entire planet – but that simplicity is part of their charm.
Not everyone is likely to want to create a terrarium entirely with moss, though, which is where you start to see the functionality of moss in the terrarium environment. When you water plants, obviously the goal is to ensure that the plants gain the benefit of having ready access to it. But the majority of the water evaporates through the soil, before the plant can even reach it, meaning that you’ve got to water it regularly to ensure that the balances are maintained. When it comes to a big houseplant, that’s pretty easy to do, as you’ve got a wide margin for error. An extra day or two without water, and it will probably recover without any ill effects. But in a terrarium, where there is little soil and it’s easy to accidental overwater or underwater your plants, moss can act as a great preserver of moisture. Because it covers the exposed surfaces of soil, it dramatically slows the process of evaporation that can potentially seriously hurt your plants.
Of course, it’s not right for every terrarium. It would look particularly out of place in a desert-inspired garden, and sometimes the dark brown colour of good, rich earth is an excellent counterpoint to vibrant green leaves, but as we said before, it’s an important tool in the garden designer’s handbook, and it shouldn’t be neglected!