The Beginner's Guide to Aquarium Plants
Welcome to the fastest growing segment of the aquarium hobby! As a beginner planted aquarium keeper, you may have been given very good advice, or very poor advice, or both, regarding the care of aquarium plants. We at AquaFlora Nurseries are hobbyists ourselves, and aside from providing the best plants we can to other hobbyists, we also want everyone to be successful at building a beautiful and healthy aquarium. Aside from our website, there are a number of other great sites that provide information, plants and accessories about aquarium plants, like aquatic plant central and the Barr Report. Our site also has articles and ideas for planted aquarium design, so keep checking back as we update and add content.
At a rough estimate, there are approximately 400-500 species of aquatic plants (plus numerous cultivars) that show promise for use in aquariums. It is possible that in time, we will discover a great many more. However, many of these plants either grow too large for home aquariums, are very difficult to propagate (and thus expensive), or show unattractive growth. There are also many species of plants that are marginals, which means they grow at the edge of water, but do not survive long term submerged in an aquarium. Species like Dieffenbachia, and Spathyphyllum are not suitable. Unfortunately, many suppliers of ‘aquarium’ plants do not bother to label such plants as Terrarium plants, so consumers will buy a plant for their tanks only to have it die within a month of two. The best advice I can give about avoiding such as waste of money is either to research ahead of time, or buy plants from a company that does not grow terrarium plants (AquaFlora only grows aquariums plants!).
So, how do we grow these plants beautifully in the aquarium? Fish tank keepers think this is difficult, but it is actually quite simple. This article was written to introduce the reader to the concepts and ideas of aquarium plant growing. Each of the major concepts also has its own article written for those that are interested in further information. We are providing readers with our observations and tricks we have learned; however, we recognize that there are many successful methods for growing plants. For this reason, we will try to provide as much general information as we can, so that the reader can decide for themselves which products in the marketplace will work for them.
Freshwater aquarium plants, like all plants, require energy and nutrients to grow. We as hobbyists provide the energy in the form of lighting, and most often as fluorescent lighting, and sometimes metal halide lighting for larger tanks. However, more is not always better. This is because nuisance algae also utilize the light. As a general rule, we recommend approximately 1.5 - 3 watts per gallon of fluorescent light for an aquarium between 25 - 120 gallons. For smaller tanks, they require more, approximately 3 - 4 watts per gallon, and larger tanks require generally 2 watts per gallon. However, as you will read elsewhere on the internet, the watts per gallon rule of thumb can be quite misleading. Unfortunately, light is difficult to measure, and so until a new test is developed, hobbyists must rely on watts per gallon. The approach we suggest is to start with lower light, and once you’ve had the aquarium running for several months, add more light if you believe it will help. Do not start out with high light, as this will almost certainly lead to algae issues.
Lighting duration is not of critical importance. There is some evidence that longer duration, above 12 hours per day, can lead to algae issues. Whether this is due to longer light, or perhaps fluctuating CO2 concentrations towards end of day, is not clear as of yet. Colour temperature (Kelvin rating) is also not of critical importance, as long as the range is about 4000-12,000 degrees K. I prefer a colour of 6500 K to view the plants (which corresponds to sunlight at midday at the equator), while others like to include 10,000 bulbs, but I have noticed no discernable differences under different bulb colours. The major differences occur between brands of bulbs, rather than colour temperature. I have long used Philips for my 6500 K T5 bulbs, but many others work just as well.
Nutrients are essential for normal growth and development for plants (and all organisms). While all are vital, some require more attention in the aquarium than others. Depending upon light levels, additional carbon dioxide (CO2) may need to be injected (please view the article devoted to Carbon Dioxide for a complete discussion). In low light tanks, around the 1-1.5 watts per gallon range, additional CO2 will probably not be necessary. However, as light increases, plant metabolism increases, and nutritional requirements increase. For moderate and high light tanks, we suggest aiming for 30 ppm CO2. This target is slightly above the needs of the plants, and below the toxicity level for fish and other inhabitants of the aquarium. Measuring CO2 is another weak area of our hobby; however, there are a couple of methods. Our preferred method is the drop check method; please see here for my two cents worth of discussion on drop checkers (DC).
Many people are also successful using pH measurements to determine the pH shift that occurs using CO2 injection. This method is accurate as long as the pH probe is functioning properly and there are not unaccounted for sources of acid or base, such as phosphates, from fertilizers or tap water. Since we recommend adding phosphates as fertilizers, pH shift method will be inaccurate. I have laid out more of this argument in this article (link).
Finally, plants require macro and micro nutrients. The macronutrients are nitrogen, potassium, and phosphorus. We recommend using a fertilizer that will introduce 10-30 ppm nitrate, 10-50 ppm potassium, and 0.5-2 ppm phosphate. We do not recommend any other form of these nutrients (DO NOT USE AMMONIUM! NH3/NH4+ will induce algae for sure). We have had great success using a method call Estimative Index, which has been popularized by Dr. Tom Barr.
Micronutrients are also essential for growth, and a number of commercial fertilizers provide the necessary micros. Tropica AquaCare, and Seachem Flourish are both recommended products, as well as our own brand of fertilizer.
Other aquarium water parameters necessary for success would a GH and KH of 3-6 degrees (some plants can handle more, some can handle less, but as a general range that is suitable for all the plants we have experimented with and grow in our nursery). Temperature is not a critical factor, as long as the tank is maintained between 18-25 degrees. Most plants will grow below this range, but many will start to die above this range. For specific plant temperature ranges, please view our plant lists.
These are the basics of aquarium plant care. Plants are not difficult to grow, assuming their minimum requirements are met. Feed the plants nutrients, give them CO2 if they need it, and just enough light, and you will have a gorgeous aquarium in no time! There are many message boards and forums around, like aquatic plant central and the Barr Report, that can offer newbies advice and help with any issues they encounter. After all, there are more than 11 million households in the USA with an aquarium (that’s one out of 10!), and we feel every one of them deserves the benefits of healthy fish swimming contentedly through groves of aquarium plants!