I have always been curious about water-based planting systems. It was not too long until I heard of aquaponics and hydroponics. I used them both so I can tell you what the differences are to avoid you browsing through the web, across articles and journals.
On small hobbyists and domestic scale, hydroponics is a better option because it is cheaper, lower maintenance, and beginner-friendly. However, on a business scale, aquaponics systems are the best as its higher income generation from both plants and fish products.
If you are someone like me back then, reading through this article might help in answering your questions like “When is hydroponics better than aquaponics?” or “When is aquaponics better than hydroponics?” Discovering this has been life-changing for me, it might also be for you.
The main difference between aquaponics and hydroponic systems is their components. Hydroponics focuses on plant production. Whereas, aquaponics incorporates fish with herb or vegetable gardening.
Hydroponics is a system of planting wherein the plant roots are submerged into a nutrient water that serves as its main source of nutrition for growth and development. Some of the techniques that fall into this category are deep water culture, nutrient film technique, ebb and flow, and wick systems.
Aquaponics is a subcategory for hydroponics. It uses principles of hydroponic gardening partnered with aquaculture. This means in this system, you are not only growing plants, but also fishes.
Aside from this, both systems differ in many ways such as capital, water, nutrient requirement, pests and competition, plant harvest quality, harvest quantity, and income generation.
Hydroponics is perfect for beginners whereas operating aquaponics will be optimum with technical knowledge and skills both in crop science and aquaculture.
Aquaponics system requires a higher initial capital investment because of the large amount and type of equipment required such as fish tanks, suspended solids clarifier, and filters.
The figure above is a simple design for aquaponic systems. Aside from a separate tank for fishes, there is also a need for cleaning devices such as a clarifier to reduce the fish waste, feed remnants, and biofloc; and a filtering tank to sort out remaining solids.
With all those additional components, we can say that indeed, aquaponics is expensive.
If we are going to contrast this to a hydroponic system, where anyone can DIY, hydroponics would win by default! This makes it an easy choice for every garden beginner since materials for hydroponics are way cheaper compared to aquaponics.
In hydroponics, the water is replaced every 2-3 weeks, or at the end of every harvest season. In aquaponics, the water continuously circulates.
The recirculation of water supports the idea of growing many fishes using small amounts of water. In the process, aquaponic practitioners treat the water to remove toxic waste products. Non-toxic nutrients and organic materials then accumulate.
These by-products from the fishes are transported to the hydroponic unit to be used by the plants. Afterward, the water is transported to the fish tank once again and recirculates.
On the other hand, hydroponic systems are advised to change water fully every 2 to 3 weeks. This practice supports sanitation in your system. Remember, that clean nutrient water is the foundation of a productive hydroponic system.
The main advantage of an aquaponics system is its limited use of nutrients. This is contrary to hydroponics which needs fertilizer inputs.
Indeed, nutrients are the number one expense in hydroponic farming. It is also a critical factor to monitor! The major advantage here is that you can control what nutrients your plant gets.
For example, if you notice yellowing on the leaves, which is one of the signs of nitrogen deficiency, you can easily add nitrogen fertilizer in your water.
On the other hand, aquaponics requires a little number of fertilizer inputs. This is because the organic matter from the fish tank is already a rich source of nutrients. Along the process, the ammonia from fish wastes is converted by nitrosomonas to nitrite. Then nitrite is converted by nitrobacter to nitrate—which is a beneficial nutrient for plants.
This efficient biological conversion makes this system a replica of a mutual ecosystem, where every element supports and benefits each other.
Pests, such as algae, is more of a problem in hydroponics since, in an aquaponic system, the fishes consume these organisms.
Algae is a real problem in any hydroponic system. They block the roots and compete with resources available in the nutrient water.
Fortunately, in an aquaponic system, fishes can consume algae. Channel catfish, plecostomus, and mozambique tilapia are among the best fishes that are good eaters of algae.
In a hydroponic system, algae can proliferate under poor management practices. Remember that sunlight and nutrients favor algae’s growth. Thus, it is essential to use opaque reservoirs or cover any possible point of entry of sunlight towards the hydroponic water.
Furthermore, plant pathogens and transport faster because of the water circulation, especially in active systems such as the nutrient film technique. But these can be solved with cultural management such as the addition of disinfectants or hydroponic system cleaning.
In scientific studies, lettuce showed better harvest performance in aquaponic systems; while tomatoes, eggplant, and spinach are compatible with both systems.
Several studies have proven that aquaponics can really grow healthy plants; however, hydroponics still provides better quality for more plants. Quality indices used in these studies are yield, leaf area, and weight.
In a technical aspect, aquaponics might promise more harvest i.e. fish and veggies/herbs. But in terms of crop production alone, harvests from both systems are comparable with each other.
Since aquaponics incurs a higher capital that invests in two different commodities, it is also expected that it would have more harvest.
In small-scale farming, aquaponics will generate higher revenue since the farmer can sell both products. Whereas, hydroponics will earn more when done on a large-scale.
Small aquaponics farmers have two markets—the vegetable/herb market and the fish market. This is the reason why it can generate higher income. Furthermore, since aquaponics is an organic system, the farmer can ask for the issuance of organic certification, which can further allow higher prices for the farm’s products.
In this aspect, we also need to consider the large-scale. In such a setup, it is projected that hydroponics can actually be profitable since it has a smaller capital requirement than a commercialized aquaponics system.
Hydroponics is a better choice for household garden beginners because it is cheaper and much easier to operate. In a business lens, it is profitable for both small-scale and commercial scale.
Compared to the required technical knowledge in aquaponics, hydroponics is a more friendly option to start your gardening journey. There are passive hydroponic systems such as deep water culture that are low maintenance.
If you are planning to enter the business world, monocropping will be a profitable option. When we say monocropping, you will just focus on one plant. With this focus, you can just purchase the nutrient needs of that specific plant. For instance, if you are growing lettuce, you can only purchase nitrogen fertilizers since it is essential in leaf development.
Aquaponics is promising as a tourist spot i.e. farm-to-table restaurants since in recent years many people are appreciating the idea of local and organic produced food. Income generation is also higher compared to hydroponics in this system since farmers harvest both fish and crops.
People are drawn to every organic concept. Since the aquaponics system mimics an ecosystem, aquaponics practitioners can be sites for school field trips, farmer education programs, and tourist destinations. Beyond this, a farm-to-table restaurant might also be a viable idea if you want to venture in aquaponics.
In a technical aspect, aquaponics has a more efficient system to utilize water and nutrients since it favors nutrient recycling for both the fishes and plants.
Aquaponics and hydroponics both use less space, consume less water, fasten plant growth, and support year-round production compared to conventional soil gardening.
Furthermore, both systems can support the growth of most plants such as lettuce, tomatoes, spinach, basil, eggplant, strawberries, babyleaf, and even cucumbers.
Some studies revealed that plants like lettuce grow faster in an aquaponics system compared to a hydroponics system. This is because they have 24/7 access to nutrients such as nitrogen in the form of nitrate, which are organic by-products of fish.
Nitrogen plays a huge role in leaf development as it is a major component of chlorophyll. Thus, when nitrogen is always present, healthy growth of leaves is expected. This is also the reason why leafy vegetables are commonly grown in an aquaponics system.
- “An Overview of Aquaponic Systems: Hydroponic Components” by Pattillo, D.A. in North Central Regional Aquaculture Center Technical Bulletin Series
- “Aquaponics vs. Hydroponics: Production and Quality of Lettuce Crop” by Pantanella, E. et al in Acta Horticulturae, International Society of Horticultural Science
- “Comparisons between Aquaponic and Conventional Hydroponics Crop Yields: A Meta-Analysis” by Ayipio, E. et al. in Sustainability 2019
- “Hydroponics, Aeroponic and Aquaponic as Compared with Conventional Farming” by AlShrouf, A. in American Scientific Research Journal for Engineering, Technology, and Sciences