The substrate you build it with ultimately determines the success or failure of your terrarium. Soil is literally and figuratively the foundation of an ecosystem, just like your glass.
But before we dive into terrarium substrate recommendations and guides, let's define some terms and clear up some misconceptions so we're all on the same page.
What is the substrate of the terrarium?
substratumis a fancy collective term for soil and other growing media. Terrarium substrate in particular is usually a bit different than other growing mediums as most terrariums do not have drainage and therefore your substrate must be adjusted.
You can buy pre-made terrarium substrate or make your own, but there are a few qualities to consider when choosing:
- Water retention -How much moisture can the substrate hold? This is determined by the composition of your substrate.
- Nutritious -In general, people do not add much fertilizer to their terrariums as there is a high chance that this will "burn" the plants as excess fertilizer cannot be washed off. You should choose a substrate with already abundant nutrients available.
- soil compaction– Repeated watering will leave some soils hard and crusty. This makes it very difficult for air to flow through the soil and for roots to spread. Additives like perlite or pumice help keep the soil loose and brittle.
What is a bioactive substrate?
bioactivesubstratumit is just a substrate intended to accommodate the life cycles of the microfauna and microflora that live in the substrate. It is ideal to have a robust microbiome with a full range of decomposers, denitrifying bacteria, springtails, various worms, some fungi, and some moss or algae. The roots of an ecosystem are in the soil (literally), and healthy soil gives the system resilience.
You don't need to buy a bioactive substrate, you can easily do it yourself. Simply get a handful of soil from any healthy outside soil and mix it in with any store-bought soil you already have. You simply inoculate your store-bought sterile soil with whatever critters live outdoors.
A bioactive system is more resilient and resilient than a non-bioactive system, but they also tend to change over time. This may not be desirable if you are building an aesthetic terrarium that is meant to remain static and not change over time. For most people, watching the rise and fall of plants and fungi is half the fun of a terrarium, so Bioactive is the way to go.
Terrarium Substrate Layers
There is a tendency to create very different substrate layers in terrariums, usually something like: gravel, charcoal, maybe a bit of sand, soil, peat, and then whatever plants and decorations you need.
Layers of terrarium substrate are not required.. The order in which you bring in the different substrates doesn't matter at all (as long as you're not trying to root plants in gravel or charcoal). It also doesn't matter if they are cleanly separated because they have no real function beyond aesthetics.
It is true that there is stratification in the natural substrate, but on a much larger scale than we can replicate in our own little part of an ecosystem. The first layer of soil in the real world (although it is more commonly called earth).Horizonte) is hethe cape, which means organic layer. It consists mainly of plant material not completely decomposed. It goes from 0 inches to 6 inches deep before the second layer (theA layer, which is called topsoil) begins.
That 6 inches is deeper than most terrariums anyway, and wild plants seem to do just fine without 4 layers in their root zone.
The fallacy of the tales of drainage of terrariums and raised floors
The real reason I warn against layering is that you are inclined to create a drainage layer. The need to place a layer of rocks at the bottom of every terrarium, container, and pot seems ingrained in the human psyche.
and it's wrong.
I often make enemies with this attitude because it is a well-entrenched part of conventional wisdom that has been passed down from generation to generation. Areintuitivethat water must drain from the soil into a layer of rock. You've probably always done it this way and your plants are doing great, thank you.
Drainage layers and raised floors are built with the intention of removing water from the substrate to prevent root rot, but they do the exact opposite. Due to a phenomenon calledraised water table, water tends to remain in the substrate, which has a larger surface area (eg, small soil particles) and is composed of organic matter (including soil).
Throughcapillary action, the product of wateradhesiveYconsistentproperties, water is able to resist gravity to a certain extent. This is how plants draw water from their roots to their leaves. It's also how the water chooses to stay in the soil instead of the nice layer of gravel you put in the bottom of the pot.
The result of a "drain layer" or "double bottom" is that it only reduces the effective depth of the tank by much, which is not ideal. The ideal scenario would be a container of infinite depth (like Earth) to allow water to soak to the bottom, away from the roots of the plants. For this reason, deeper substrate is always better.
The only time a drainage layer or false bottom is effective is when it's actually, you know,drains. Like the terrarium. In reality, this is only possible with a water pump in the soil layer or, more rarely, with a tap on the outside of the terrarium.
When you take a few steps back from the overwhelming urge to put rocks everywhere, it doesn't even make logical sense. Suppose the water drains into the rocks, now what? Does it sit there forever until you fill the bin? Or… does it evaporate very slowly? Where? In the lowest soil, right next to the fresh roots that are most susceptible to root rot? And it keeps evaporating creating a slow release root rot machine.
HM Yes. It is better not to make a drainage layer. If you want an even deeper argument against it, check this outthis postI wrote on my succulent website (it even has photos).
Do closed terrariums need a different substrate?
Enclosed or enclosed terrariums have very different needs than their open equivalents.As with most things in soil, our main concern is how it interacts with water.
A closed terrarium with lots of light has a restricted version of the water cycle. The water evaporates, condenses on the walls of the container, and then drips back onto the floor. With no other place for the water to go, the container remains more or less as wet as the day you sealed it.
In this case, it is not necessary to add water-retaining ingredients to the substrate; it will be wet 100% of the time. Sealed terrariums generally require plants that can tolerate constant root flooding, such as pothos, but you can broaden your selection of suitable plants a bit by increasing airflow through the soil.
Using inorganic materials with large particle sizes, such as perlite, prevents the soil from becoming too thick and should allow for some airflow.
Do open terrariums need a different substrate?
Open terrariums are suitable for a much wider range of substrate qualities, as you can always tailor your watering to any problem. If you want to take a more practical approach, you can increase the water retention of your growing medium with coco coir or something similar so you don't have to water as often.
Choosing the best substrate for a terrarium
Asking what is the best substrate for a terrarium is the wrong question. Not that the container needs a specific type of soil, you're not asking what the best soil for terracotta pots is, are you?
When putting together a terrarium substrate, you actually need to consider a few things:
- What individual needs does each plant or animal in the terrarium have?
- Which are thecommunityterrarium needs? Where is the overlap in the care requirements for all organisms that ensure that everyone is happy with the care you are giving to the terrarium as a whole?
- Does the terrarium have a real drain? Almost certainly not. Do you need to adjust the composition of the substrate to compensate for this?
- Optional: underground aesthetics. Dirt can also be beautiful. Although not necessary, layers of substrate can make a terrarium look better.
How to make substrate for terrarium
The substrate for your terrarium can be as simple or complex as you like. Unless you're planning to add very specific plants like orchids, you can probably even use outside soil.
If you want to mix up some terrarium substrate to keep on hand, try a recipe like this:
- Half an inch of activated carbon
- 2 parts normal potting soil
- 1 part perlite or pumice stone
- live or dead peat
Place them in the terrarium in that order, although you may want to plant a few before applying a top dressing.
Common Terrarium Substrate Ingredients (and Uses) List
If there's one thing I'm trying to get across in this article, it's that there's no one right way. It mainly depends on the plants you have and the maintenance you want to do to the terrarium. Here is a list of terrarium soil and accessories you could add:
- Potting soil: sterile, fertile soil for plant roots. Contains no microbiome
- Perlite: Reduces soil compaction, increases airflow
- Pumice stone - reduces soil compaction, increases air circulation
- Vermiculite - retains water and slowly releases it over time
- Coconut husk/coconut fiber: retains water and slowly releases it over time
- Peat moss – mix into soil to retain water or use live as a mat
- Peat – low soil pH
- Activated charcoal: antifungal, reduces odor
- Gravel - only for aesthetic reasons, not very functional
- Arena - only for aesthetic reasons, not very functional
The best pre-mixed terrarium substrate
If you don't want to go through the hassle of mixing soil and creating all kinds of layers, I would recommend getting a pre-made mix of terrarium substrate.
They're a little tricky to find, as a search for "terrarium substrate" usually returns results geared toward reptiles or amphibians. If you're interested in growing primarily plants, it's hard to know if the product is still a good fit or not.
best for all purposethe premade terrarium mix is from Josh's Frogs, one of the leading authorities on bioactive terrariums and nurseries. It's formulated to hold water without getting soggy, so it works well with most plants.
That's all that can be said about soil and terrarium substrates. Any questions I didn't get to? Ask in the comments!