Can you imagine it? A tropical paradise, lush leaves swaying gently in the breeze...er...current. That's right, a whole world of plants that are very happy living their entire lives under water. Not just green plants either, but a whole plethora of colours and textures. Reds, golds, purples. Short, tall, feathery, fat leaved varieties.
The first thing you will need, of course, is an aquarium. They come in many sizes. 5, 10, 35, 72, 150 gallon. Probably a few in between. You could probably use a goldfish/beta bowl if you want to start small. Very important if you have found a used aquarium, fill it full of water in the bathtub or outside and make sure it does not leak!!
Next you are going to need some gravel. Decorative aquarium gravel is relatively inexpensive and comes in many colours. You will need at least 3 inches. This will be your soil, the growing medium to anchor the plant.
Your plants will need some water circulation. Circulation helps get the nutrients to the plants and good water movement stimulates healthy growth.This can be acomplished by a good old fashioned filter. Hopefully, when you acquired your used aquarium, you received the filter apparatus with it. It just needs to run, you do not need to have the foam and carbon filters inside.
Light. Depending on the type of plants you want to grow, this varies. Most aquariums come with a good lighting fixture in the hood. For moderate light plants a good rule of thumb is 2 or 3 watts per gallon of water. Full spectrum fluorescent lights are a good starting point. The ones we use on our plant stands. Reasonably inexpensive and easy to install. Window light would work, but sunlight promotes algae growth, and then you have a whole other problem. 12 to 14 hours of light every day is sufficient.
Temperature. These are tropical plants after all. The water temperature should be kept between 70-80F. Heating units for aquariums are available in any pet store. Reasonably inexpensive.
CO2. Carbon dioxide. Essential for lush plant growth. Do you need it? Depends on how involved you want to get. I grow underwater plants without it, but then I have fish in my aquarium. The fish waste provides my plants with most, if not all, of the needed nutrients. Granted, if I didn't have fish, and wanted to focus entirely on the plants, I would more than likely invest in a C02 system. There are many different ways to get C02 into the aquarium. Some are easy, some are more involved and unsafe if small children or pets are around. Personally, something like this one here, would be preferable for my situation.
Fertilizer. Your average plant fertilizer should not be used with aquatic plants. Too much phosphate or nitrate can cause algae. Trace elements are the more important. There are a number of aquatic plant foods available that are specifically designed for this purpose. They are also safer if you decide to add fish to your jungle.
Plants. Most pet stores that sell fish, sell aquatic plants. Be careful though. Some of the plants they sell are not true underwater plants. They will survive for a while but eventually fade and die. Some house plants I have seen being sold as aquatic plants are Spider Plant and Aluminum Plant(Pilea cadierei).
Having an underwater tropical paradise might be a wee bit more expensive than a terrarium, but once established is relatively low maintenance. My best advice to you would be to start small and simple. See if you enjoy it, research a bit, and go from there. There is so much varying information on growing aquatic plants, and a million different opinions on how to do it. One could write a novel. This article is just to provide the very basics, hopefully to get more people interested in this unique growing method. It is very rewarding indeed to grow your own underwater paradise.
Special thanks to our own Tropicalmajic for providing me with her amazing aquatic plant photos.