Creating a Tropical Terrarium or Vivarium
Keeping reptiles and amphibians in living terrariums has rapidly increased in popularity over the last decade. An enclosure that combines live plants and animals together looks attractive and may be beneficial for certain species. Many people who haven’t kept animals in a terrarium often avoid them because they assume that they are difficult to create or keep clean. When properly planned and cared for, nothing could be further from the truth. Although terrariums take time and planning to set up, they are not complicated to make. The key to long term success is careful planning during the beginning and keeping up with regular maintenance, such as spot cleaning and pruning plants.
Unfortunately, not all reptiles and amphibians can be kept in terrariums or vivariums because of their size, amount of waste produced, or behavior. Avoid most large species of reptiles or amphibians because they often trample plants and are messy. Species that burrow or dig are also poor candidates for a tropical terrarium because they often uproot plants. Herbivorous species and those from arid environments should be avoided for obvious reasons.
Tropical terrariums are moist and it is important that the bottom portion of the cage is waterproof. Standard glass or acrylic aquariums work well and are widely available. Specialty reptile tanks with sliding or hinged front doors also are a good choice. They work particularly well for terrariums that house skittish animals which may be frightened by a hand entering from above like with a standard glass aquarium. Realize that the size of the cage that is used will limit what types of plants can grow and what features can be included inside. Larger enclosures are preferred, because they provide you with more options.
The type of cover or lid that is used depends on the needs of the reptile or amphibian that is being housed in the tank. Screen covers can be purchased from most pet stores and provide excellent ventilation and also allow for ultraviolet light to enter, which is important for many species. Screen covers can be modified by taping plastic wrap or glass over part, which will help maintain high levels of humidity. In some situations, it is also appropriate to use a solid glass cover. This is a good option if the humidity in the room the terrarium is within is especially low. Ventilation can be provided by cutting out a large hole and covering it with window screen silicone in place. Good air circulation is important for most herps and many common plants, so although humidity is important, ventilation may be more so.
When planning the cover, make sure that it accommodates the types of lighting that are required for the animal in the terrarium. UVB rays are important for many species of reptile and amphibian. They will be filtered out through glass and fine screening so light bulbs that produce UVB radiation need to be placed over a screen section of the cage. Basking and spot lamps often crack glass and melt plastic, so use caution if heating a terrarium with these devices.
The type of background that is used can have a large effect on the aesthetics of a terrarium. Simple black paper or poster board can be taped to the outside of the tank. This is okay for small terrariums with terrestrial animals. However, in most situations it is best to attach an actual background to the inside of the terrarium that plants can grow on. This creates a whole new dimension to the terrarium and works great for tall tanks. It is easiest and often required to attach the background to the enclosure before putting anything inside so this is often the first step. There are many different backgrounds available. Most can be attached to glass with aquarium-safe silicone sealant, which can be purchased from pet stores or hardware stores.
Below is a short list and description of background materials that are commonly used:
Cork bark forms an attractive background to which epiphytic plants can be attached. Bark flats are sold at many pet stores. One of the best qualities of cork bark is that it lasts a long time in moist conditions. Natural cork bark flats are usually curved to some degree and leave a small gap between the middle of each piece of bark and the glass. This empty space should be filled with soil, moss, expandable foam, or gravel to prevent animals in the cage from becoming trapped or inconveniently hiding between the glass and the bark. Alternatively, pressed or cut cork bark panels are sometimes available from specialty terrarium supply companies which are completely flat and won’t leave a gap between the glass and the bark.
Tree Fern Panels
Tree fern panels are the roots of tree ferns that have been shaped into flat board-like sections and our popular with orchid hobbyists. These panels are dark black to chocolate brown. Tree fern panels look great and work well for mounting epiphytic plants. Unfortunately, they are rarely harvested from the wild in a sustainable way. A better alternative to tree fern is EpiWeb, which resembles tree fern panels but is made from recycled products.
Coconut Fiber Sheets/Panels
Coconut fiber panels are made from the long fibers that look like hair and grow on coconuts. They are readily available at garden centers as well as from terrarium supply companies. Coconut fiber is inexpensive and practical, however it can be a little difficult to mount plants onto.
Artificial Foam Backgrounds
In recent years, painted replica rock or wood backgrounds have gained popularity and become widely available. However, these foam backgrounds inserted into a living terrarium, in my opinion, look tacky. They may be improved by applying silicone and dried coconut husk fiber or other natural material over their painted face, though in this case it may be even better to start with plain Styrofoam and sculpt your own background rather than spend the money on the fake rock.
Rather than purchase a background and glue it to the back of the terrarium, many people prefer to make their own. There are dozens of techniques and styles. One of the most common methods is to use a spray-on polyurethane insulation foam, such as Great Stuff – Gaps and Cracks. This can be sprayed onto the back of the cage and layered to create a unique shape and texture. This foam is then followed most often by black or bronze silicone sealant in order to make it waterproof and safe. Directly after the silicone sealant or other waterproof substance is applied, dry coconut husk fiber or peat moss is pressed into it to give the background a natural appearance. Josh’s Frogs has a good tutorial about how to do this here. I have also put up a step-by-step post about how I build a foam background. A similar method for creating a terrarium background is to use Styrofoam insulation sheets. These large sheets are cut and shaped using a foam cutter, covered with silicone sealant and coconut husk fiber or peat moss as mentioned above, and then attached to the back of the cage. There are many other techniques for creating a background in a terrarium, the above mentioned two are only a couple common ones.
While some terrarium enthusiasts opt for growing mainly epiphytic plants and using a thin substrate or almost none at all, most tropical terrariums will need both a potting media for plants and underneath a drainage area for excess water to drain into. Without this drainage area most soils become waterlogged quickly and will spoil, disturbing the biological cycles that occur within.
A drainage area can be created a number of ways. Gravel is cheap and easy but heavy. Using 2 or 3 inches (5 cm to 8 cm) of pea sized or larger gravel beneath the soil is an easy way to create a drainage area. In large terrariums it may be better to use a lighter substrate beneath the soil instead of gravel. LECA (lightweight expanded clay aggregate) is an excellent substitution for gravel. It can be purchased through some garden centers and hydroponics supply stores in the United States under the brand name Hydroton. A false-bottom is also a good way to provide a lightweight drainage area, and this involves using a porous plastic material on legs that holds the soil an inch or two above the bottom of the terrarium, where water can gather.
Whatever drainage substrate you choose, place fiberglass window screening or similar material over it so that the soil does not slowly fall below into the water or mix into the gravel or LECA.
There are dozens of recommended terrarium soil mixtures online and in books. Many successful soil mixtures used in tropical terrariums are based off of coconut husk fiber. This product is made from coconut shells that have been ground into a soil and then compressed into a dry brick. When placed in water, this brick expands back into a moist soil-like media. Coconut husk fiber decomposes very slowly, has a neutral pH, is made from a renewable resource, and is cheap. It can form the majority of the substrate used in a tropical terrarium.
In the past I have also used peat moss in place of coconut husk fiber, but the more that I learn about peat moss the more I hesitate to use it. Peat moss takes hundreds of years to form and currently is mostly collected unsustainably by destroying bogs and other wetlands. In the terrarium, it decomposes quickly and needs to be changed often. It also is slightly acidic which can be harmful to certain terrestrial amphibians. The one practical application that I’ve found for it is when it is used to grow live moss or carnivorous plants. Most types of live moss and carnivorous plants grow best on a soil that is slightly acidic and peat moss works well in these situations, but is best mixed with other ingredients.
Mixing other materials with coconut husk fiber will help provide drainage for plants. Orchid bark, fir bark, or coconut husk chunks can be mixed in for this purpose. Orchid bark can make up the majority of the soil in areas where plants that do best in well-drained soil are used, such as bromeliads. Sand, tree fern fiber, shredded oak leaves or leaf compost, milled sphagnum moss, activated carbon, and chopped live moss can also be added. Adding a small amount of leaf compost to terrarium soil mixtures can introduce beneficial micro-organisms that help to maintain the terrarium though be wary of introducing pests this way too, such as snails or slugs.
When housing terrestrial amphibians or small reptiles, placing a handful or two of leaf litter over the substrate once the terrarium is planted is especially helpful. It also improves the appearance of the terrarium. Indian almond, live oak and magnolia leaves are often favored but make sure to collect them in an area that is free of pesticides and to wash them with water before use.
There are many different items that can be used to furnish a terrarium. They may serve a purpose (such as a basking site for small lizards or shelter for nocturnal frogs), or may simply improve aesthetics.
Cork bark slabs can be used to hold soil back in certain areas, creating small hills and cliffs. Cork bark tubes can be planted with epiphytic plants to make them look like over grown fallen logs. Driftwood can be purchased at many pet stores, and can be used as a centerpiece for the terrarium. River rocks and slate can be used as cage decor and add a nice touch when they are placed along side of a water area. Generally, terrariums look best when only one type of wood is used. Too many different types clutter the terrarium and make it look unnatural. Wash all wood or rocks with hot water before placing them in the terrarium. Don’t worry if they mold over for the first week or two. Sometimes it can take time for driftwood or cork bark to adjust to humid or damp conditions, and during this time they may grow white fuzzy molds which usually go away on their own.
Before using a piece of wood or rock consider the care requirements of the reptile or amphibian you plan to keep. Does the animal need a basking spot? Arboreal or terrestrial hiding spots or egg-laying sites? How about a few hiding areas? Wood and rocks can be attached to higher areas in the terrarium with silicone sealant to create a dramatic effect, or even better, included in a homemade background from the start. Ensure that all rocks and wood are stable and will not be knocked over by the reptiles or amphibians being kept.
The type and amount of lights to use depend on the plants and animals being kept. In small terrariums that have a few low light-tolerant plants in them, and an animal that does not need any special type of lighting, a single fluorescent tube can be used. Tall terrariums with plants that like bright lighting may need more. While standard T8 or T12 fluorescent tubes are still widely used, newer LED lighting designed for planted aquariums may be better options. For particularly tall terrariums you may need to consider even stronger lighting options, such as metal halides.
The color temperature or Kelvin rating of the bulbs used has a large impact on the appearance of the terrarium. Bulbs with a low color temperature below 5000K often give a yellow or red hue to the terrarium. Those with a high color temperature above 6500K produce a purple or blue tone. Different people favor different terrarium appearances, but I generally prefer using bulbs with a color temperature near 5500-6500K. These bulbs are often referred to as “natural white” or “daylight” bulbs because they produce a bright white light similar to the color temperature of the sun during midday. Multiple bulbs are not always needed, but will help increase plant growth and generally improve the appearance of most terrariums. In addition to color temperature, the CRI (color-rating index) rating of a bulb is also important to look at. This rating determines how the colors of plants and animals in the terrarium will appear. The sun has a CRI rating of 100, so when choosing a bulb try to locate one with a high CRI rating, preferably above 80.
The animals in the terrarium may require additional lighting to the types mentioned above. Most diurnal lizards need a light bulb that produces UVB radiation in order to process calcium from their diet. Many amphibians benefit from UVB radiation as well. Both fluorescent and power compact fluorescent bulbs are available from pet store that produce UVB radiation. Some species also require a basking spot in the cage that is produced by using an incandescent light bulb. It’s important to use an accurate thermometer to check the temperature of this basking spot to ensure it does not get too hot.
Live plants make terrariums what they are. They add a dimension of life that cannot be replicated with artificial plants. Different types of plants require different environments to live in just like animals, and not all species grow well in a tropical setting. High humidity and moist soil will cause many species to rot or mold. These conditions also cause many plants to grow too quickly, or get too large too fast which makes them unsuitable to use. It can be advantageous to seek out plants from specialty terrarium supply companies rather than the local garden center to make sure they are a good fit.
Epiphytic plants can be grown on backgrounds or pieces of wood in the cage to create an arboreal area for small animals to climb. Ground covers and low growing plants can transform the soil into a green living carpet. Tall broad-leaved plants can be used as center pieces in the terrarium, and plants with small leaves can be used to accent them. Below is a list of some commonly available plants that I have used successfully in a tropical terrarium, clicking on the scientific name of most will display a photograph of the plant.
|Scientific Name||Common Name||Comments
|Aglaonema modestum||Chinese Evergreen||–|
|Alocasia species||Elephant Ear||For tall terrariums only|
|Begonia thelmae||–||Climbing/trailing small-leafed Begonia|
|Cissus discolor||–||Attractive vine; requires regular pruning once established|
|Crypthanthus species||Earth Stars||Needs well-drained soil|
|Ficus pumila||Creeping Fig||Fast growing vine, great for backgrounds|
|Fittonia species||Poke-a-dot Plant||–|
|Humata tyermanii||Rabbit’s foot fern||Can grow large|
|Marantha tricolor||Prayer Plant||–|
|Neoregilia species||Bromeliad||Small and miniature varieties are perfect|
|Pellaea rotundifolia||Button Fern||–|
|Pellionia repens||Watermelon Vine||Another easy to grow attractive vine|
|Peperomia obtusifolia||Baby rubber plant||Grows quickly, very hardy|
|Pilia species||Aluminum plants||Grow very quickly|
|Philodendron species||Philodendron||Train smaller varieties along driftwood, cork, or backgrounds|
|Polypodium polycarpon ‘Grandiceps’||Cobra Fern||Mount above substrate|
||Ressurection Fern||Epiphyte to mount above substrate|
||Philodendron ‘ginny’||A Philodendron-like vine with supportive leaves|
|Saintpaulia species||African Violets|
|Scindapsus aureus||Pothos, Devil’s Ivy||Another classic, grows fast|
|Scindapsus pictus||Silver Vine||Does best in well-drained soil|
|Selaginella species||Club Moss, Golden Club Moss||Great ground cover, requires high humidity|
|Syngonium podophyllum||Arrowhead Vine||Hardy, may quickly outgrow a terrarium|
|Tillandsia species||Air plants||Epiphytes to mount high in terrariums, needs to dry out thoroughly between waterings|
|Vesicularia dubyan||Java Moss||An aquatic plant that can be grown on land when kept moist|
Plants that are purchased at local garden centers should be washed thoroughly with water before being placed in the terrarium and ideally grown outside the enclosure for some weeks to let chemical on their leaves dissipate. Many stores use fertilizers, pesticides, leaf shiners and other chemicals on their plants that could be harmful to reptiles and amphibians. Purchasing plants through the mail from specialty terrarium supply stores is usually the safest route to go.
Many people desire a lush green carpet of moss to grow in their terrarium. While it is certainly possible to successfully grow moss, not all types of suitable for use. Avoid species from temperature climates, which may need a dormant period in winter and often only last a year or so in the terrarium before they turn brown, never to return. Tropical mosses can be purchased from terrarium supply companies that are better, but still can be tricky to grow. There are also ethical concerns about using commercially harvested moss in a terrarium.
Rather than purchase moss for use, most terrariums will develop moss on their own given time and this is the preferred way to grow moss in a terrarium. You can also use hardy plants that resemble moss as an alternative. Java moss (Vesicularia dubyan) is a superb option. It’s an aquatic plant sold at many tropical fish stores, but when draped over a moist land area or log emerging from the water it also grows well. Ricca (Riccia fluitans) is another option that can be grown out of water in very moist, very bright conditions and is often a better alternative to actual moss.
Setting it All Up
- Select an enclosure and lighting. Place the cage and light where you plan for it to permanently go and check to make sure it is easy to access, there are electrical outlets nearby, and the stand or table will support the weight.
- Attach a background and let this dry until there are no strong smells of silicone sealant or other adhesive in place.
- Add the substrate. Drainage layer first, followed by window screen or other divider, and finally soil.
- Furnish the enclosure with driftwood, cork bark or other items. Seal the tank up and give everything a good watering or heavy misting. Let it sit for a few days if you can and make sure you like the way it looks.
- Plant it. Tie epiphytic and vine-like plants onto driftwood or other items over clumps of sphagnum with fishing line. Use U shaped pieces of wire, like large staples, to press live plants into the background over small clumps of moist moss. Once the upper parts of the terrarium are planted, add others in the soil mixture. Avoid straight lines, plant in odd numbers, don’t use too many different species.
- Wait. Give the terrarium at least a week or two, and preferably longer, before adding any animals. During this time, check the temperature throughout the enclosure and address any problems that arise.
- Stock the terrarium. Once you are certain the environmental conditions within the new terrarium are suitable for the species of amphibian or reptile you plan to keep, add animals and enjoy!