FAQ's & Answers

I apologize for having not posted in a while; between a hectic life schedule and battling the flu, time has most certainly gotten away from me! But now I'm on the mend and I see that Spring has firmly arrived in Vancouver, so maybe it's worth getting out of bed. All whining aside, in this post I want to address a couple questions I regularly get asked regarding watering, replanting, and mold.

How often should I water my terrarium?

Watering schedules are dictated by three factors: plants, vessel, and location. For a more traditional terrarium containing tropicals plants, mosses, ferns, air plants, bromeliads, orchids, etc. you will want to keep humidity levels high, and the soil just moist (not soggy!). If the terrarium is more of a xeriscape (cacti, succulents, sansevaria, etc.) let it dry out between watering. Succulents are great at telling you when they need water: if they start to shrivel up and look like the skin on your elbow, it needs a drink--otherwise leave it be! If the terrarium is mostly or entirely enclosed, it is unlikely that you'll need more than the occasional spritzing of water just to help maintain the humidity. If the terrarium has more of an open top, you'll probably have to keep a closer eye on the moisture levels. As terrariums do not have drainage holes to allow excess water to run out, it is essential that you NOT OVER-WATER! If in doubt, stick your finger right into the soil; if it is dry and inch down you can water, but if it is soppy, let it dry out and keep your eye on it. The location of where you place the terrarium affects it as well. If you put even a full enclosed terrarium by a heat source, you'll probably have to water it fairly often. If it is in a bright window getting lots of indirect light, you'll probably have to water a little more regularly than you would if it were sitting on a coffee table with less light. Is is in a moist room (such as a bathroom)? You may never have to water it! You also have to take into account how dry the air is in the location in which the terrarium will go. Lots to consider! Generally, a light water once a week for tropicals is fine, and once every two-three weeks for a succulent terrarium. When you do water, make sure you water evenly, making sure that every plant gets some water to its roots. Watering unevenly can lead to plant death or mold. 

A xeriscape terrarium like this requires very little water

Does my terrarium need replanting?

The Bean 2.0

Again, it depends on the plants. Plants such as cacti, succulents, sansevaria, moss, palms, and bromeliads don't have much of a root system so you generally don't need to worry about them getting root bound.  Succulents LOVE to grow up all close together in tight little bunches; they're like a happy little family. Don't destroy that happy little commune that they've built up! If you do though, they will probably forgive you because they're cool like that. On the other hand, some tropical plants get quite large and are quite competitive for space within a container. Ficus elastica wants to be a very large tree, diefenbachia becomes a large plant, ferns and mosses often take over... In such instances, it really is up to the person maintaining the terrarium as to whether they remove the gangling or disproportionate plants. For instance, I recently had to replant my beloved "The Bean" (long story short, it got vandalized  my heart broke), and when doing so, I found that that the diefenbachia was starting to struggle as it had simply grown too large. So I left it out, but salvaged the palm (and the turtle) for the new terrarium. If a plant has leaves that are turning yellow or a succulent that has going black and mushy (a.k.a. rotting) it may need to be replaced because it has been over-watered and is a potential threat to the rest of the terrarium. If you have leaves that are turning crusty and brown, you probably need to give the plant more water, or the terrarium is getting too much direct light and the plants are literally frying. In this case, you can probably get away with just removing the dead leaves rather than removing the whole plant.

What do I do if I see mold?

Mold is pretty much inevitable with a terrarium, so if you have it, don't worry it isn't you, it's the fact that a terrarium is a living breathing environment full of organic matter and moisture. Mold can happen for a number of reasons. Often it happens because the container is over-planted and the plants within it don't have the room they need to grow and breath. Just as often it is because there is moisture trapped somewhere and the heat produced from the photosynthesizing plants is providing a delightful environment for mold to grow. If you see mold on the ground within your terrarium do things immediately: try and remove as much as you can, and clear the area around the mold so as to let air get to it. Then, let the terrarium dry out a bit. You may be over-watering, or you may be watering unevenly. Figure that out, and keep your eye on the mold situation. If you see a molding plant, don't panic! If it is just a molding leaf, remove the leaf right away and try to get more air into your terrarium by either letting the humidity and moisture levels drop or by removing the cover (if it has one). If the entire plant has turned, remove it immediately, check the soil where it was to make sure there is no mold, and again, let the terrarium dry out and get more air. Keep a close eye on the welfare of your other plants to make sure there is no more mold. But again, don't panic if you see mold! It's not you, it's the fact that you are playing with a tiny environment of living, photosynthesizing organic matter. It happens. A little mold is nothing to worry about, just make sure it doesn't become a problem.

The NW Special

I hope that this has answered some of your questions! What I really hope is evident here is that you do not have to be a so called "green thumb" to keep a terrarium alive. It's just the rudimentary science we all learned in primary school! Plants need a degree of moisture to photosynthesize  Too much moisture + not enough oxygen = mold. Just think about how our own world works: it rains sometimes, it's dryer sometimes. If it rains too much or too hard, it floods, plant life washes away and things drown. When it is too dry, plant life is suffocated and dies. But at some point, everything tries to balance out. Find the balance!