Building Carnivorous Plant Terrariums
Above all else remember this: Carnivorous plants like light over everything else. Lots of light is more important than high humidity. Humidity of 40% will keep the vast majority of the cp's happy.
Terrariums are great for sundews and cephalotus but not much else. Flytraps need a dormancy and huge amounts of light, so just grow them outside. Sarracenia get to big and also need huge amounts of light and a dormancy. Nepenthes grow tall fast so a typical terrarium is not well suited for them. But a terrarium made for Nepenthes can work well.
You can make a terrarium out of just about anything. Take a look at the Containers page to see examples of some small terrariums. You can also use fish tanks/aquariums or build one out of plexiglass, glass, wood and glass or just about anything else. The main thing is to have a clear viewing area and a clear top to let your light shine in, unless you build the lighting into the lid as below.
You can build a carnivorous plant terrarium out of plexi glass, or wood and plexi glass. If you use wood paint the inside with a gloss white latex paint. Do not use after painting for 10 days. Caulk the inside corners before painting but not with silicone if you are painting it. Plexi glass can be held together exclusively by silicone caulk. Just run a 1/4" bead along all inside corners. Build any way you like but you need to have at least the front and top clear, unless you can build a lid like shown. Another option would be to cut a section out of a wood lid where the light will sit to let the light shine in.
|This one was made of 1/8" plexi-glass with a wood lid and the lighting is internal. It has a plastic 1/2" tube running down one corner and across the bottom. The hose is plugged at the end and has 1/8" holes drilled through each side every 4" that is touching bottom. More on this bellow.
On the top right you can see the computer fan hanging down. It blows air OUT of the terrarium and draws it in from the far end through another vent. A cotton wick can be added over the intake to cool and add moisture to the air as it is drawn in.
|This is what the terrarium looked like a few months later. U. livida has spread nicely and hordes of D. Nidiformis is springing up because I let them flower. The forked sundews took some time to get used to the lower light levels but seem to be adjusting well now. I treated the tank with insecticide once, which D. adelae did not appreciate at all. The picture doesn't show it well, but the LFSM is slowly starting to grow.|
|There is a sight glass in the bottom left corner to monitor water level. I generally raise it to around 2" every three days or so, it drops down to a 1/2" within an hour. The site glass is made by simply placing a piece of plastic roughly 1" wide at an angle to block the soil.|
|This is closer to what the finished patented terrarium looks like. The wood base and top keeps the thin plexy from flexing over time. The top pieces need to have a groove cut down the center to allow it to slip over the plexi, we use a 1/2" deep grove 1/16" wider than the plexi used. This one has a pond and river with a mister in the pond since heliamphora will reside in this one, at least until they outgrow it.
The hood houses three compact fluorescent bulbs.
click for bigger pic
Keep in mind what it is your going to be planting in it. Make sure you give yourself plenty of height for them to grow. You may want to stop and think about what kind of lighting your going to need. If you are placing it by a window where it gets some sunlight then 3' cool white fluorescent bulbs should do the trick. If sunlight is not going to play a helping hand then you will need two - four 4' bulbs, depending on your width. The bulbs need to be suspended very close to the lid. Or you can use the flourescent light bulbs, get the daylight ones.
Roughly 20% of the top should be open to keep humidity from becoming 100% +. You can use vents instead but be prepared to use a fan to dissipate moisture and heat. Most carnivorous plants are happy in 40 - 50% humidity. Nepenthes are happy in 60 - 70%.
Use the container to set your potted plants in or make it one big planter to plant the plants in directly. The up side to placing the pots in it is the ability to take them out on humid days. I like planting them in it, I think it looks much better.
Make a mix of 10 parts perlite to 1 part horticultural charcoal. Make a 1/2 in. deep level layer of this mix in the bottom. The charcoal will help aerate the water, reduce mold should a problem arise, and keeps it smelling fresh. I even sprinkle some charcoal around on top. Charcoal is very important unless you enjoy a musty odor.
Next add your medium. If you are growing different types of plants then taper the soil depth from six or seven inches on one side down to around four inches on the other side. This allows some plants to remain in wetter soil than others and gives those plants that have extensive root systems room to grow. The unit above tappers down to about 3" and is pure sand in this shallow area. I did this to accommodate U. Livida.
If your handy at building or making things and your making a fairly good sized terrarium you can get some rubber tubing, I use 1/2 inch. It needs to be long enough to go from corner to corner on the bottom of the terrarium and up one side. Drill several 1/8" holes along the section that will lay on the bottom. Use silicone caulk to fill the end of the hose that lays on the bottom so water can't come out of the end. Put a decent bead of caulk up one corner and run the hose up the corner you caulked. If you cut the hose just short of the top you can use a cloths pin to hold the top and put something heavy enough to hold the hose down on the bottom. You don't have to seal the hose to the bottom of the tank because you can secure it with soil. This hose will be your watering hose. Use a funnel to stick in the top of the hose to add water, this way you can still bottom water. I place the hose in a corner that is going to face out so I can see the water level. Just make sure you can easily get access to it. Don't fill the hose to fast or it will erode the soil, if the water is backing up in the hose you are pouring to fast.
You can help alleviate some heat by taking the transformer out of the fluorescent light housing and re-mounting it on top of the housing as pictured. I can not tell you how to do this because I do not want sued if done incorrectly. Its pretty easy for those of you comfortable to try though. Just don't blame me if you burn your house down!
Terrariums are great for Sundews, Nepenthes and Pings. Most all other carnivorous plants can be grown outside or in a sunny window. Nepenthes will have to be trimmed back from time to time, see the Nepenthes propagation page for instructions.