Q: About terrarium bubblers.


A bubbler

A: Once you have a terrarium, you will of course want to stock it with every plant you can cram into it. Space will be a premium, and you will probably not have room for anything extraneous, like empty pots or photographs of you dressed up like a borg at a science fiction convention.

However, there is one non-plant that I strongly recommend you consider adding to your terrarium, and that is a terrarium bubbler. This is what I call a device that provides water on demand, fed by gravity. It is particularly useful if you are going to be gone on a trip for a few weeks, and will not be able to water your plants. Even a mostly-sealed terrarium will slowly lose water, and the trays will dry out and the plants will perish. (I have heard many stories of people losing their plants at the hands of inept spouses or family members during trips....you are warned.)

It surprises me, but people are often mystified by how terrarium bubblers function. The best way to understand them is to just make one and observe it in operation. Take a bottle with an air tight lid (like a plastic 1-liter soda bottle), and drill a small (1 cm/0.5 inch) hole in its side, just about at the bottom of the bottle. Remove the lid, put your thumb over the hole, fill the bottle with water, and replace and tighten the cap. Point the hole towards yourself and uncover the hole. Note that the water spills out of the hole, and all over your embarrassing lower regions. Now you have a big wet stain right where you don't want to have one. Boy do you look silly.

Ah, but if you repeat the action, this time putting the bubbler in a bowl, note that when enough water comes out of the bubbler to submerge the hole, water no longer comes out of the bottle. Cool, huh? This is the same principle that makes office water dispensers work. (It works because, for water to exit the bottle, air must be able to enter...but if the hole becomes submerged, air is prevented from entering. Gravity is defied, at least for the moment!)

A terrarium bubbler will extend the time between your waterings. When your plants run low on water, the bubbler will take over and dispense its contents. It may extend the time between waterings by a few weeks, and that might cover your business trips. Experiment with the size and placement of the hole---do not make the hole too small, because a surprisingly small amount of algae can seal it.

The bubbler I show on the photograph above was made by using an inverted bottle, with a notch on its opening. However, inverted bubblers are unstable. I prefer to use ones that operate with the bottle in its normal orientation. Oh, also make sure that you use a bottle that is really sturdy. Soda bottles with flimsy, collapsible walls are no good for this purpose.

Page citations: Rice, B.A. 2006a; personal observation.