Bio-Active Terrarium Plants

Authored by Jeremy Kosonic

Completed Bioactive Chameleon Enclosure Courtesy of Karen Stockman

Ever since the beginning of herp keeping, people have wanted to keep their animals in a natural setting (click Jump Link to read more about bio-active)

Unfortunately the “spartan method” became more popular, making those with truly naturalistic enclosures a small minority.

Now that people are realizing how boring this way of keeping is, they are finally going back to nature—and what better way to get back to nature than using live plants (click the link to search for live plants)

Why use Plants?

Plants have many benefits when added to vivaria; so much so, that many keepers of rare species include plants because of their benefits. Live plants are really a “must-have” for most species.

After all, what’s the point of keeping herps if you can’t enjoy them in a natural setting?

Plants help stabilize soil, making burrows stronger, and microhabitats more stable. They provide the animals a place for cover from predators, weather, or each other, and also provide places to complete their reproductive cycles (such as Oophaga spp. (click for complete treatment of Oophaga spp.) and Ranitomeya spp. and their use of Bromeliads and Heliconia spp.). Much like in aquaria, plants will also use up the ammonium and nitrates in the soil thus completing the nitrogen cycle: something completely ignored by most herp hobbyists.

Another huge benefit of using live plants is they can act as a “canary in a coal mine” so to speak.

Animals tend to hide illness (in an attempt not to show predators their weakness and avoid predation), meaning if something is wrong with the enclosure you likely won’t know until it’s too late. Plants succumb to bad conditions relatively quickly, and if the plants are from the same area/habitat as the animals you’re keeping, then they can be an early warning sign before it’s too late. This is why biotopes are great; having any generic “desert plant” won’t show the health of the system as they all have separate preferences, while using plants found in the same location as the animals will better represent the health of the system because they all have similar needs.

Start a Plant Tank

Misting Nozzle within Bio-active Terrarium

Set aside an empty tank (or 7) for propagating and growing out plants for use in vivs. This basically gives you an almost unlimited supply of plants as long as you can propagate them. It also helps prevent the spread of pathogens from using plants from a different enclosure with animals in it. The plant tank can be as simple as a 10 gallon or plastic bin with sphagnum moss or as elaborate as a large indoor greenhouse with a misting and drainage system.

Processing/ Cleaning Plants
If you are buying and using plants bought at the local Home Depot or Garden Centre, it is a good idea to clean the plants before using them in enclosures. This cleaning process gets rid of virtually all of the insecticides, pesticides, and unwanted pests.

This process is simple, yet important.

Carefully remove all the soil on the plant.
Soak the plant for 10 minutes in RO, distilled, or dechlorinated water to allow it to soak up as much water as possible.
Soak the plants in 5-10% bleach solution ( roughly 1.25 cups per gallon) for 5 minutes. Note: this may kill some of the more fragile species such as moss, some orchids, etc. For those, either soak for only 2-3 minutes, or use a weaker bleach solution.
Rinse the bleach solution off of the plant. Make sure you can’t smell the bleach anymore.

Soil

One of, if not the most important part of keeping plants is the soil they will be planted in. Obviously this isn’t a worry for epiphytes, but for terrestrial and hydrophytic plants, it is crucial. The soil in the enclosure should be well draining (a false bottom is very useful for this) to prevent the roots from sitting in stagnant water. You may have to compromise a bit when it comes to plants and animals. Put the animals needs first, while still allowing proper drainage for the plants. If the animal needs a hard, compact soil (such as for some arid species), consider mixing some Turface™ in around the rootball of the plant. The soil mixes mentioned in the Bio-Active article (here) are suitable for most plants. The cacti soil link provided above is also a great resource.

One of the more common substrates used in “bioactive” tanks is a 50/50 mix of ground coconut fiber or peat and sand. This is unsuitable for most plants in tanks as it decomposes quickly and compacts, likely resulting in anaerobic conditions. The best substrates to use for plants are those that breaks down slowly.

Mounting Epiphytes
As previously mentioned, many species of plants do better when they are planted above the soil on objects such as rocks, twigs, and backgrounds. If planted in the soil, these plants will likely rot at the base. There are many methods for mounting epiphytes in vivaria, but the most common ways are as follows;
Stuffing into cracks
Simply shoving the roots or stolons into cracks or holes tight enough to keep them upright is probably the easiest method. This also makes it look very natural for lithophytic and chasmophytic plants. If planting bare root, sphagnum moss can be stuffed into the crack along with the plants (not needed for most bromeliads).

Toothpicks

Insert two toothpicks into the background, place them on an angle, creating an ‘X’ with the toothpicks [see picture]. Place the plants between the toothpicks and the background. This will hold the plants long enough to establish a root system that will support the plant. By this point, the toothpicks will decompose and feed the bugs.

Wire staple
Bend a heavy gauge wire into a ‘U’ shape, placing it around the base of the plant and into the background. Once roots have established, and the wire is no longer needed, remove the wire.

Fishing line/ cotton string/ zip ties
Place the plants on the branch with a small clump of sphagnum moss (again, not needed for bromeliads) and wrap the fishing line or cotton string around, securing it to the branch. For zip ties, tighten it around the clump of moss, plant and branch. You may need to use 2 or 3 to keep it all together. If using fishing line or zip ties, remove once the roots have established and they are no longer needed. Much like the toothpicks, the cotton string will hold it long enough to establish, eventually decomposing.

Drilling holes
For stoloniferous species such as (Neoregelia spp.) and other bromeliads, a hole can be drilled into wood, rocks, backgrounds, etc. and the stolon jammed into the hole.

Placing Plants

There are many points to consider when placing your plants in the enclosure. Much like planting a freshwater aquarium, there are many styles and considerations when doing so.

Here are a few:

Use an odd number of plants
Using an even number of plants tends to make things look too uniform or planned. Planting in odd numbers gives it a more “random” and natural appearance.
Put the shorter plants up front

Putting the smaller plants up front helps give a sense of depth, and allows them to get the most light possible. While this is something to consider, don’t layer all the plants from shortest in the front to tallest in the back. This gives it a “Grocery shelf look” and is often not appealing. Planting one or two larger plants up front still helps create depth and can look amazing.

Consider the biology/growth habits
When choosing plants, don’t think about what they look like that second. Think about what they will look like in 2-3, or even 5 years from now. That little Bromeliad pup won’t stay small. Will planting it there eventually shade out the plants below it? Will plant ‘X’ get enough light if planted there?

Also consider growth rate. If planted in an appropriate spot, Plants WILL grow; sometimes REALLY fast. Species such as (Pothos sp.), (Ficus pumila), or (Tradescantia spp.) grow super fast and need to be kept under control before they out grow the enclosure and choke out all the other plants. Make sure you keep fast growing plants trimmed to allow the slower/smaller plants access to light. Lastly, place plants where they would naturally grow in the wild. i.e. Keep (Cryptanthus spp.) on the ground, and (Pleurothallis spp.) and (Neoregelia spp.) mounted up high.

Use mostly green plants
Using mostly green plants will allow the animals to be the focal point of the enclosure. Too many colourful plants can look gaudy and unnatural— especially a tank full of different Neoregelia cultivars. Don’t get me wrong, one or two colourful plants can look really good in a terrarium, but there is definitely a point where it’s just too much.

Make sure they can withstand the inhabitants

Courtesy of Next Generation Boas

This one is pretty straight forward. Don’t put plants in an enclosure where they will easily get crushed. For example, don’t put small orchids or delicate ferns in with Emerald Tree Boas (Corallus caninus), Iguanas (Iguana spp.), or reticulated python (Malayopython reticulatus saputrai). They will be destroyed in a matter of minutes. Keep the delicate plants with small and delicate reptiles. Alternately, don’t put expensive or specimen plants in with herbivores.

Don’t use too many plants/ Keep the density low
If you look at the floor of a forest, you’ll see that while there is a large variety of plants, they are fairly spread out (perhaps with the exception of epiphyte laden branches and rocks). Try to keep the number of species low. This will not only look more natural, but it’ll be a bit easier to keep track of the plants.

Plant in clusters
In the wild, plants tend to grow in clusters. Replicate this by planting them in odd number groups.

Lighting/ Shade
This goes hand-in-hand with growth habits above. Don’t plant huge plants that will shade out everything under it. Make sure the light is strong enough to reach the bottom if needed.
As mentioned above, what may seem bright inside, may actually be deep shade outside. Don’t be afraid to provide bright lighting. It will help the plants grow, and is very unlikely to hurt the reptiles in any way (keep in mind the animals experience the same light levels the plants do in the wild). While it’s virtually impossible to provide too much light in a vivarium, some species of plants such as (Ludisia spp.) and other forest floor species can get “sunburnt” under too much light. Bright lighting can also cause cryptic reptile species to hide more. Too bright of lights can also make the tank hard to look at, causing it to look unnatural.

Air Flow
As previously mentioned, many plants need access to air flow in order to dry out and prevent rotting. This can be as simple as placing them close to vents, or installing a small computer fan like many dart frog keepers do. Stagnant air is never good in tanks, and air flow is appreciated by all – including the animals.

Consistency
Be consistent. If you’ve chosen to do a Peruvian biotope, don’t put a (Ludisia bicolor) in the tank. If planting in clumps, don’t put one species all over the tank. Pretty straight forward.

Pick a focal point

Similar to using mostly green plants, choose one specimen plant to be the focal point. These tend to be the colourful plants. Too many colourful plants and the focal point is lost. A big (Neoregelia cv.) or a clump of a showy (Gesneriad sp.) can make really nice focal points.

Reptile “Safe” Plants

There are many “Reptile Safe Plant Lists” out there online; some better than others. While using non-toxic plants for herbivorous species is important, this is pretty much a useless practice for species that won’t actively seek out plants to eat. As long as the plants aren’t overly sharp, or are too small to eat the inhabitants in the case of carnivorous plants, and won’t get trampled, most plants are fine in enclosures with carnivores, and some omnivores.

Most reptiles are also pretty intelligent when it comes to what not to eat. Many herbivores will try it and never touch it again if they don’t like it. So I tend to not worry too much when it comes to “safe plants”; however being cautious is by no means a bad thing!

Numerous non-toxic reptile plant lists can be found with a simple Google search, so I won’t list any here. However, if you are looking at a plant that isn’t on the list and you are unsure, snap a branch or leaf. If a sticky white sap, or an onion smell is expelled, err on the side of caution and don’t use it. Not all plants with sticky white sap or the onion smell will be toxic, but it’s better to be safe than sorry.

Let the plants grow in
You may have noticed an almost excessive use of the words “establish” and “stabilize” throughout this article —That was not an accident. This is an important aspect to using plants in an enclosure with live animals. If the plants are not given a chance to establish (send out roots and stabilize itself in the soil), then the animals could dig down, uproot the plants, destroying them in the process. Also as mentioned numerous times, the plant roots help stabilize the soil, in turn making burrows and microhabitats/niches better. Not only will allowing the plants to grow in make the plants happy, it will also make the animals happier since it provides them with a more natural environment. Allowing the plants and enclosure to grow and establish for at least a month (preferably more) will allow the plants to send out roots and for the bacteria and mesofauna/inverts to populate the tank to levels capable of handling the animal waste (similar to cycling an aquarium before adding fish). I will often setup the enclosure while the animals are still in quarantine, giving it a good 2-6 months of growth before putting any macrofauna in.