Backgrounds

Have you ever wondered how to make a professional looking background? This article explains how to make backgrounds using the most popular methods: cork bark, polyurethane foam, flevopol and bentonite clay are all discussed below. If you are interested in sculpting fake wood and rocks, please check out the decor section.

No Background

A terrarium does not require a background. In fact, if you are going for an overgrown vivarium look, you might not even see the background after your plants have grown in. Also, the lack of a background can be useful if you are create a 360 degree display tank, or want to show off something behind the terrarium, such as a mural or stone wall. However, a background certainly has its merits. Aesthetically, a background visually impress your guests and let them appreciate what a beautiful terrarium has to offer. Functionally, a background can provide vertical hiding spots for your animals, making them feel more secure to explore the vertical space of the terrarium. Also, a background increases your habitable surface area and thus can increase your microfauna population. Also, depending on the background, the increased surface area can help maintain higher humidity.

Cork Bark

Cork bark is an easy way to make an attractive background. Cork holds up well under high moisture, as evidenced by its use in wine soppers. Cork bark comes from the Cork Oak Tree, a species of oak. Cork trees are farmed to produce the corks used for wine bottles. Every seven years, the farmers harvest cork by removing bark from the tree in a way that doesn't harm the plant. The first harvest, after seven years of growth, is called virgin cork bark. While virgin cork isn't very useful for making bottle corks because the bark is fairly thin and very curved, it makes a great terrarium background. The bark has plenty of nooks and crannies for frogs to hide and plants to be mounted. It can be attached to the background by [INSERT METHOD]. An alternative to virgin cork bark is pressed cork pannels. These are made of corkboard and pressed flat. Cork panels are easy to work with, all you need to do is cut them to size and glue them to the back of the terrarium. Their flat nature means that they are less effective at providing hiding spots for animals. If you use cork panels, I suggest you mount some plants across the surface to make it more three dimensional. With cork bark, you are limited to the pieces that nature formed, which may or may not work well in your terrarium. A fully synthetic alternative, such as polyurethane foam (brand name="Great Stuff") gets around this obstacle.

Great Stuff

Great Stuff is the brand name for polyurethane insulating foam used to seal up gaps during construction. Other brands exist, and may work better or worse than Great Stuff, but Great Stuff is the most readily available (from a home improvement store) and what will be described here. Great Stuff comes compressed in a spray bottle. After contact with air, the liquid produces gas, which causes the foam to expand greatly in size. This is used to create a three dimensional background, which can then be carved and covered in a more natural looking finish (Great Stuff is bright yellow and unattractive). Here is a guide to creating a background out of Great Stuff. While this process may look overwhelming, it is actually quite easy and a good creative outlet.

Step 1) Cover the glass in dark silicone. This will both hide the ugly yellow foam and help keep the foam from peeling off of the glass. Make sure the glass is clean before applying the silicone, or the silicone may peel away in the future. Let the silicone dry overnight in a well ventilated area.

Step 2) Spray on the Great Stuff. Easy does it! Don't put on more than about 1” of foam at a time. The foam will continue to expand for up to 48 hours. If you are attempting make an extra thick, build up layers over several days. If you make the foam to thick all at once, the inside will not cure well, which will cause problems later on. Wait 3 days after the last foam application before moving on to the next step.

Step 3) Carve away the excess foam to get a final shape that you like. Don't stress out about the details, but spend time making interesting shapes and think about where you will put plants and which you will make hiding spots.

Step 4) Cover the foam in a natural looking surface. The most common method of doing this is to mix up some DRY peat/coco coir/sphagnum in a bowl, cover the foam in brown silicone and then smash the mix into the silicone. This will create a nice surface with the appearance of dirt. This surface will not wick water, however.

Step 5) Let dry for a weak (until the silicone smell is gone and it has completely cured), and then mount your plants.

Bentonite Clay

A more recent background method to gain popularity is the use of bentonite clay. The bentonite clay method, also called the kitty litter background, uses wet clay for the background. Dry sodium bentonite is sold as natural clumping kitty litter, hence the name “kitty litter background”. Calcium bentonite is also available, and may act as a source of calcium for the frogs. In this straightforward and simple method, bentonite is mixed with peat or soil, and spread over the background like spackle. This creates an attractive background, which wicks water well and thus raises humidity. In my experience, frogs seem to enjoy crawling on the bentonitew, more so than any other background I have tried. Bentonite is also a great substrate for moss growth, so pressing some moss into a new bentonite background is a good way to get lush moss growth on your back wall. Currently there is a major drawback to bentonite, however. If the bentonite is not kept under constant high humidity, it will slowly crack and peel off of the glass. Trials are currently underway to prevent this from happening.