Aquaponics vs. Hydroponics
Aquaponics and hydroponics share certain similarities – they’re dynamic cropping systems that involve growing plants without soil; using organic inputs for healthy produce; and directing nutrient-rich water solutions to the plants. Most importantly, they provide an invaluable counter-alternative towards traditional methods of agriculture.
The absence of soil as a growing medium, indicates that everyone can be a hydroponic or an aquaponic gardener, irrespective of the size or other variations of their houses – like access to sunlight and certain implements (both aquaponics and hydroponics are a vital component and adaptation of the DIY economy).
These systems are also vital for the environment, because they follow the principle of recirculation of water, which saves tremendous amounts of water compared to soil-intensive agriculture and gardening, while producing higher yields.
An additional benefit is the protection that indoor gardening has against pest and bird attacks, which automatically implies that chemical fertilizers, insecticides and pesticides become redundant.
There is, also, the bonus of not relying on traditional cropping patterns – indoor growing opens a plethora of possibilities to the grower, lending a greater sense of agency over the elements – light, temperature, nutrition and space.
Aquaponics and Hydroponics – A Difference in Science
Here begins the points of departure between these two systems, involving the creation of different kinds of ecosystems and adoption of a different scientific approach towards the growing of plants. In simple terms, while hydroponics is the growth of plants without soil, using nutrient-rich water, aquaponics is a closed-loop circuitous system wherein aquaculture (rearing of fish) and hydroponics combine, to create a syncretical bind.
This is the most basic difference in science and method – one can argue that, therefore, hydroponics is actually a subset of aquaponics, even though variants of hydroponic gardening have been found in the ancient world in Babylon, Egypt, China and a lot of rice-growing regions in Asia.
Aquaponics and Hydroponics – Advantages and Disadvantages
Relatively, aquaponics is a much more recent phenomenon, even though crude evidences have been found in the practices of the Aztecs and parts of China in medieval history between the 14th and 16th centuries. The growth of aquaponic gardening has also been heralded by the developments in modern technology, especially in the last few decades.
Aquaponics comes down to the balance and management of three living organisms – plants, fish and the nitrifying bacteria, that process the ammonia that is produced as a result of fish waste. Let’s take certain parameters and weigh the differences between these two systems, which will also help us understand the ways in which they work (and don’t). We provide a balanced overview of both systems, leaving it up to potential growers to decide what suits them better.
1. Cost-efficiency and the sale of produce:
In the setting up, hydroponics has a definite edge in this arena. While the cost of setting up is generally more expensive in an aquaponics set-up, it’s the daily maintenance where the real pinch comes in. Fish tanks require a constant source of energy (in our previous blog, we also argued that having a backup power-source is vital).
Yet, aquaponics relies on fish-waste to feed the plants, whereas hydroponics requires investment in plant-rich nutrients, different variants of N-P-K fertilizer (i.e., Nitrogen-Phosphorous-Potassium), which is expensive. Commercially, aquaponics growers argue that the option of selling dual quantities of produce – fish and plants, gives them a definite competitive edge over hydroponic producers operating on the same scale. In a later section, we’ll find out if this is, indeed, true.
2. What Setting-Up Entails:
In our previous article (How to build an Aquaponics System), we discussed the components of an aquaponics system – a fish tank, another tank/container, PVC pipes (for vertical system and NFT), a water-pump, air-pump, a growing bed with media (for the media system) and biofilter. Conversely, a hydroponics set-up is arguably simpler (and cheaper!). It would also require less space, and can be carried out in a basement or a space without any sunlight.
As we saw in the previous section, it is perhaps a myth that commercially, fish provide a greater financial edge. In real terms, fish need to be purchased in the first place, and then reared and fed. The fish also create the conditions for the requirement of a larger media bed – while hydroponics can do with a 6-inch bed, aquaponic gardening must be carried out with at least a 12-inch growing bed, to give the fish ample space to maneuver.
Finally, hydroponics is a simpler set-up, in the sense that it requires little to none accompanying eco-system, growing media, etc. to support the roots, bacteria and micro-organisms. Aquaponics requires a self-sufficient eco-system that can allow micro-organisms and bacteria to flourish, without which fish waste cannot be processed.
3. Level of organicity:
Make no mistake, this is one of the most important factors that goes into plant cultivation. Modern agriculture is plagued by inorganic substances – chemical pesticides, herbicides and pesticides, which further cause damage by seeping down to the ground water table, both usurping it and damaging it. Lands have been driven fallow and infertile by repeated chemicalization that seeks greater and greater yields.
Hydroponics is not always an organic exercise since there is a constant requirement for a sterile environment. The science is up for debate across the spectrum, with proponents for and against this statement, though there are alternatives. For example, some argue that coco-coir (coconut fiber), used as a growing medium, produces organic produce, as it has added worm castings which do the job. The jury is still out on this.
With aquaponics, organic is the norm and guarantee. After all, what can be healthier than creating a self-sustaining ecosystem, with microorganisms, bacteria (and sometimes worms) existing to both balance the pH and help process fish waste, in the form of usable nutrients for the plants? The answer is nothing – aquaponics produces the healthiest produce, head and shoulders above all other possible systems.
4. Prone to Disease:
In gardening parlance, what is called ‘root rot’ colloquially is actually a crippling disease called Pythium. Pythium is a parasitic fungus, with most species acting as plant pathogens. In both soil cultivation and water-based hydroponics, Pythium is common. In an aquaponics system, however, root rot or Pythium is non-existent, because the recirculating water and ammonification allows plants to build up a natural tolerance.
5. Yield Size and Speed:
In the first place, due to micro-organisms being present, aquaponics provides greater opportunities with a variety of fruits, vegetables and herbs that can be grown (as seen in our previous blog on ‘What Can You Grow with Aquaponics’). This is not to say that the range exhibited by hydroponics produce, by any means, is limited, but the sterile environment provides lesser room for flexibility.
When it comes to yield size and speed, it is important to reiterate that both systems provide an alternative to traditional cropping patterns, by giving more room to the grower to experiment with, and control, conditions. However, aquaponics provides an edge over both yield size and speed – 30-40% over soil cultivation and 8-12% over hydroponics in terms of size, and 15-20% faster in speed, over hydroponics.
6. Disposal of Waste:
Nutrient-rich solution water, used in hydroponics, is regularly changed to balance nutrient content, salinity and pH. It means having to throw out a solution full of rich nutrients and fertilizers, and replacing it with another, on a reasonably frequent scale.
On the other hand, by definition, aquaponics focusses on converting fish waste into usable nutrients for the plants through ammonification. It is a self-sustaining cycle with a closed-loop, which takes care of its own nutrition and waste once it’s in motion. Perhaps checking once-a-week for ammonia and pH is sufficient. This also automatically implies less day-to-day maintenance vis-à-vis hydroponics.
Aquaponics vs. Hydroponics – What Have We Learnt?
We have two highly efficient and workable models, providing a clear and better alternative to soil-based cultivation, with lesser potential for rotting, pest and bird attacks, failed yields. We have two models that provide us with the potentialities for subverting traditional cropping patterns, and growing certain vegetables and fruits all year long. In one of these models, i.e., aquaponics, we have the added bonus of not injecting water with antibiotics, as is the practice in aquaculture, where fish is reared in an open tank.
We are also left with the understanding that it is almost futile to argue the benefits of one of these systems at the cost of another, since both are so good for the environment. Growers should exercise agency and adopt either system based on what is locally available, and easier to procure, since the sustainability angle in hydroponics and aquaponics looks at reducing carbon emissions in the first place. In certain arenas, aquaponics holds a clear edge, while in some others, it is hydroponics– either way, you’re saving the environment, and helping your body at the same time.