Hello and welcome to Natural World Facts. I'm on location here in the British countryside
and I'm gonna be creating a closed terrarium.
A terrarium, if you don't know, is basically a sealed ecosystem contained in a jar, meaning
that everything that you put in there, all of the water, the nutrients, the plants, the
animals, the soil will stay in there. And they will be continuously cycled within that
jar to sustain an ecosystem that can survive for years. All you have to do is make it and
put it in a position where it can get enough sunlight.
All you're going to need if you want to follow along the video is a jar and some boxes for
collecting things. Apart from that, all the other ingredients can be found somewhere outside,
so head out to your local park, forest, even just your garden and let's see what we can
do.
I've collected a few plants, including these young ferns, as I think they'll look great
in that big jar that I brought with me. And this soil around here that covers the forest
floor is perfect for a terrarium, because all of this leaf litter, this decaying wood,
these acorn shells and old leaves, they give their nutrients to the soil and make it perfect
for growing plants.
The first step in building a closed terrarium is to create something known as a 'false bottom',
which is essentially just a layer of stones at the bottom of the jar that will separate
the soil layer from the water layer at the bottom. When the water that you put in there
soaks through the soil and sits at the bottom, you don't want the roots to be touching that.
Otherwise you'll get a lot of mould and rot.
So, I've headed out and gathered all of the stones that I need to make this. And now it's
time to put them in.
You only need your false bottom layer to be a couple of inches thick, and then we'll have
a soil layer, and then we can start planting.
I reckon that should do nicely.
The next step is to add the soil that you collected. I've got a nice big pot of it here.
I'm just gonna gently drop this into the top of the jar.
You're gonna want about 4 inches of soil in there, but before I finish doing that, I'm
going to add some of my plants because they're quite tall.
I gathered some young ferns. Because they've got such long roots, I think I'll put them
in now and add more soil on top so that they get buried. So drop them in.
I'm going to use a long stick to press those roots down into the soil.
I got some soil up my sleeve. Get some of that leaf litter in there so that when we
add the woodlice later on, they have something to eat.
Now we can start to add even more of the plants. I've put my fern in already. That's going
to be the centrepiece. And I've got lots and lots of moss. And moss is just perfect for
a terrarium because it really grows in to fill the space.
I've got some grasses as well. Just like the moss, these will really grow to cover all
that dirt at the bottom.
Now, some of these plants inevitably won't survive that long in the terrarium but that's
natural. Some do and some don't, some do better than others, and the ones that don't will
die. Their nutrients will return to the soil, so it's all fine, you don't have to worry.
If you start seeing mould, try to remove it with a pair of tweezers before it gets out
of hand.
Before we move onto the final stage where we add the insects, we're going to give this
a little bit of water. You don't want to provide too much, and it's better to have less than
more.
But it needs water. So, for best results, you're gonna want water that's naturally found
outside, whether you've collected some rainwater or found a little pond or a lake, get that.
I gathered this from a lake nearby. I'll pour a small amount into the lid of the jar so
that we don't end up putting too much in. Gonna pour it into here.
The reason that a terrarium can be self-sustaining is because it is a closed system. The water
that you've just put into yours will stay in there as long as it lives.
Just like the normal water cycle, that water will evaporate, condense on the glass sides
of the jar, and fall back down like rain into the plants.
Now for the really fun part. Get your container and head out and find some insects, because
these are going to be the clean-up crew of your terrarium. They will decompose all the
dead matter, all the mould, all the rot, anything in there that you don't want, they'll break
it down and get rid of it for you and return the nutrients to the soil. Now these aren't
essential, and I know some people are squeamish when it comes to insects, because there are
some microorganisms that'll be present in the soil you use as it's bioactive, that will
do exactly the same job. But I think adding these larger insects really allows you to
visualise these important and fundamental processes of decomposition and nutrient cycling.
If you want, follow this step too.
If anything, it's just a good excuse to get out there and relive those childhood days
of lifting up rocks and logs in search of bugs.
All the old wood that's lying around here means it is the perfect place to find the
insects that we need. And the one's we're looking for mainly are the detrivores, the
decomposers, things like the woodlice and the worms.
After I made my last terrarium video, I got a lot of people asking where the insects get
the air from in the terrarium, considering it's sealed. Now, this is actually the same
way that we get our air. The plants in here - the mosses and the ferns that I put in - do
the same job that the trees around us do, but on a much smaller scale. The animals in
there will be respiring, meaning they're converting oxygen into carbon dioxide. The plants, at
the same time, will be doing the opposite, undergoing the process of photosynthesis,
producing the oxygen that those animals need in order to survive.
So, there you have it. A sealed ecosystem in a jar. A slice of the natural world that
you can take home and put on your windowsill, and watch as it grows
and changes.
I've been joined by someone. I think it's a female red deer.