How To Turn an Aquarium into a TerrariumBy Lee Anne Stark (@threegardeners) on January 20, 2012
We have a 72-gallon aquarium. Over the years fish have passed on, the way fish tend to do. There are 3 fish left right now; kind of silly, them having an entire 72 gallons all to themselves, especially since they're all bottom feeders. It's time to renovate.
First we had to catch the fish. That wasn't quite as easy as it sounds but it was the hardest part of the whole procedure. I found an old 5 gallon aquarium in the basement. Actually, I found two 5 gallon aquariums, one 10 gallon aquarium, and a 15 gallon aquarium. I chose the 5 gallon because it perfectly suited the idea I've had swimming around in my brain for awhile now.
This would have been a much simpler process if I'd just turned one of the empty aquariums into a terrarium, but no, I had a plan.
Bearing in mind that the average household bathtub holds between 40 - 50 gallons of water (up to the overflow valve), the 72 gallons that came out of the aquarium is a lot of water. I had to scrounge up something to hold it all since it was fish water, which is basically liquid gold when watering house plants. First, I watered every single one of the 150+ plants in the house. That barely made a dent in it. I dug around in the garage and found Hubby's wine making whatchamacallits and a couple of pails. Let the draining begin!
I still ended up pouring a few pails down the bathtub drain. Once the water was out I had to deal with all of the soggy, fish-poo laden gravel. More pails, a spaghetti strainer, and a recycling bucket came into play. Scoop gravel out of aquarium, rinse in the bathtub, and then a final rinse with the reasonably cleanish water from the top half of the aquarium. It's only going to be re-purposed as the bottom layer of the terrarium so it doesn't have to be sterile. This step was mostly to get the worst of the fishy smell out and to gather another pail of liquid gold.
Once the gravel was rinsed the fun part began. The bottom layer is gravel. This helps with drainage. On top of, or mixed in with the gravel, it is recommended to use activated charcoal for odor control but I never bother with it and have never noticed an odor, unless you count that lovely, earthy scent you get when green things are growing happily in a nice humid environment. Arrange the gravel anyway you like. I tried to create little hills and valleys. Oh, and guess where I put the fish in their 5 gallon aquarium!
On top of the gravel you should put a layer of sphagnum. Again, this step can be skipped if you don't have any. I only had a tiny bit. The sphagnum helps keep the soil from seeping down into the gravel. This is kind of redundant in my opinion because you're going to end up mixing a bit of soil and gravel while planting anyway. Then comes the soil layer. Now we get to plant it!
I'd been quietly gathering terrarium type plants all summer in preparation for this event. I gathered tropicals but you aren't limited to tropicals. You could have a bog type terrarium filled with carnivorous plants, or even a desert type terrarium filled with succulents and cacti.
A few plants I can get away with, because my aquarium has a beautiful grow light fixture/hood so I'll have good light. Some plants I planted directly into the soil. Others, ones that won't bloom unless they're a tad pot bound (Streptocarpus), I just buried their pots.
One thing to remember. If you don't have a light on your terrarium (that is why I prefer using aquariums, they come with lights), you must remember to not place your terrarium in direct sun. The glass will act like a magnifying glass and you could end up cooking all of your hard work. You also need to be able to vent your terrarium to let extra humidity out. While humidity is a good thing, too much will cause mildew and fungus and all of your hard work will rot.
Caring for your terrarium is easy. Check every couple of weeks to see if it needs a drink. Water if it's dry. Remember to vent it if too much humidity builds up (you'll know this if you can't see inside for the fog). Keep your terrarium plants well groomed. Remove any yellowing or dead leaves, they mildew easily. Prune your plants if they grow too big. You do not really need to fertilize, the idea is to keep the plants small. Your terrarium will fill in quickly enough as it is. If your terrarium is near a light source, remember to turn it occasionally to promote even growing.
I hope I've removed some of the mystery surrounding terrariums. They're really quite simple and a lot of fun. They can evolve over time. I might decide a few months from now to add a waterfall or a river. Just have fun!!