Aquaponics mimics a natural ecosystem in a miniature form, resembling the way aquatic environments function in nature. The fishes are given a task in this system; eating and excreting, leading to nutrient-rich water caused by their waste. Subsequently, bacteria play their role by transforming this waste into fertilizer perfect for fostering plant growth. The plants utilize this fertilizer, resulting in water purification. The purified water is then reused to tend to the fishes, and the cycle begins again.
The collaboration between fish, plants, and bacteria in an aquaponics system results in the production of both fish and vegetables, while using the same amount of water required to obtain only one product. This self-contained system ensures minimal water wastage as the discharge of wastewater into the environment is negligible.
Aquaponics, Past and Present
Aquaponics is not a new concept as it dates back to 1,500 years ago when it was first practiced in South China, Indonesia, and Thailand. The traditional method involved growing rice in paddy fields that were flooded and contained fish. The fish waste acted as a natural fertilizer for the rice crops.
Another style of aquaponics was created five centuries after when a community located in central Mexico, identified as the Aztecs, built a vast realm. The capital city, Tenochtitlán, was constructed on the coast of Lake Texcoco. Due to the inadequate fertility of the soil in that marsh, the Aztecs constructed floating gardens which were called chinampas. These plots were formed by dried plant residue and mud. The farmers of chinampas grew maize, squash, tomatoes, and other crops on these islands. The plants could utilize the rich nutrients in the lake water which was abundant in fish excrement.
Aquaponics, which was an ancient concept, wasn’t rediscovered for its potential until the 1970s by scientists. Presently, aquaponics is becoming quite advanced and presents a sustainable solution for agriculture, which decreases natural resource usage. In comparison to traditional agriculture, aquaponics uses a remarkable 90% less water, and the crops grow quicker. Moreover, aquaponics reduces the contaminants produced from tractors and pesticides used in fields.
Aquaponic systems can be set up in outdoor settings as well as enclosed, greenhouse-style indoor environments. Implementing an indoor setup can lead to year-round food production, providing a significant benefit in regions where the weather is not conducive to farming due to factors such as low temperatures, a lack of daylight hours, and limited access to water for irrigation.
Types of Aquaponics
Today, there are three principal aquaponics systems in use. The first is the raft system, which involves placing plants in holes drilled in floating rafts. These rafts then float in fish wastewater tanks, and the plant roots are able to absorb the necessary nutrients from the water. This system is best suited for small plants like spinach, chard, and salad greens. The second system is the substrate approach, where plants are placed in pipes drilled with holes that continually circulate fish effluent water. The roots can then absorb the nutrients in the water, with the substrate mimicking the soil and supporting the plants. Many types of plants can grow using this method, but it is most commonly used for onions, cabbage, and other similar plants. The third system involves placing plants within a soil-like substrate containing bacteria that help uptake the nutrients from fish wastewater. This system uses narrow pipes to allow the water to flow, and the roots of the plants absorb the necessary nutrients as it passes by them. This method works best with plants that require minimal support, such as herbs, leafy greens, and strawberries. Vertical placement of the pipes can be helpful to conserve space.
Highly Profitable Aquaponic Crops
The crops with the highest profit margin in aquaponics are those that can be grown using minimal space and energy while maintaining superior quality. Plants that can thrive solely on fish waste nutrients, and do not necessitate additional fertilizer, require fewer resources for cultivation. Such crops typically include leafy greens, small fruits, and culinary herbs. To achieve the best return on investment, it is advisable to cultivate a variety of premium crops together with compatible fish species that are edible.
is a herb that is commonly used in cooking for its flavor and aroma.
High-quality basil is a lucrative crop due to its market price exceeding $10 per pound (0.45 kg). Well-established aquaponics farms can produce it for as little as $0.75 per pound. With a mass production value nearly ten times production costs, it can be a remarkably profitable crop. Organic cultivation and maximal density are essential to attaining the highest basil value.
With endless uses in the kitchen and as a source of pesticidal essential oils, basil is definitely one of those herbs that will never lose its global demand. It can be consumed fresh or in the form of dried leaves, drastically extending its shelf-life. Its ease of harvest is matched by its rapid growth rate, which is sped up even further in nutrient-rich aquaponic systems. Since the roots don’t have to grow far and wide to gain access to nutrients, the plant can refocus its energies on producing larger leaves.
High-value cultivars of O. basilicum such as Thai basil, Genovese basil, and dark opal basil (a cultivar that has received an award) are among the most favored. Aquaponic systems can opt to focus on growing only these cultivars. Growing basil alongside other herbs can also be lucrative. Incorporating a variety of species, although more challenging to manage, can aid in minimizing the possibility of pest infestation.
The botanical name for lettuce is Lactuca sativa.
For centuries, people have grown lettuce and it has become a popular leafy vegetable. Nowadays, there are numerous types of lettuce, each with its own distinct nutritional benefits and cost. Romaine, iceberg, butterhead, and looseleaf are the main varieties that are cultivated and traded worldwide.
Lettuce is a popular component of numerous aquaponic systems due to the high demand for nutritious leafy greens. Certain recirculating farms have the capability of cultivating diverse varieties simultaneously, which is attractive to those aiming to offer their customers a constant supply of the crop’s most sought-after types. The production of premium lettuce in aquaponics can bring in earnings of up to $16 per square foot or up to $20 for a case of 24 heads.
The insufficient nutrients present in the soil are a primary factor that hinders the growth of lettuce in conventional farms. Moreover, several bugs that invade the soil also damage the tender leaves by creating significant perforations in them. In aquaponic setups, these problems can be conveniently averted as the soil component is swapped out with a media bed that is free from pests and affluent in nutrients.
Eruca vesicaria, commonly known as arugula, is a type of green leafy vegetable.
Arugula is renowned for its tangy and spicy foliage, making it one of the most beneficial greens that one can consume. It is categorized as a superfood, with a wealth of nutrients such as vitamins, proteins, and fiber. The vital aspect of this vegetable is its intricately-shaped leaves, though its seed pods, seeds, and flowers are also edible. The fresh leaves are commonly incorporated in salads and have recently become a popular topping for pizzas, contributing to their delicious taste.
Aquaponic systems are ideal for cultivating arugula as it can thrive and grow rapidly in nutrient-rich water, outpacing its growth in conventional soil-based mediums. Two prevalent techniques for growing arugula are the deep water culture (DWC) and the nutrient film technique (NFT). DWC results in fast growth, with harvest-sized leaves ready in only 4 weeks. On the other hand, NFT is more suitable for smaller arugula varieties with roots that can fit comfortably into growing tubes.
Aquaponics enthusiasts have a fondness for this plant that grows annually due to its high profitability. In comparison to lettuce and other leafy greens, it generates more profit.
are a type of tomato that belongs to the Solanum lycopersicum var. cerasiforme variety.
One of the top yielding crops for aquaponic setups is this type of miniature tomato. If a suitable support system is in place, their stems can extend up to 6 feet tall. Once pollinated, the flowers transform into the plant’s distinctive, ample red clusters of tomatoes. To maximize output and economic efficiency, it’s best to use a Dutch bucket technique when cultivating cherry tomatoes.
The cultivation of tomatoes in Dutch bucket aquaponics involves using growth media as the rooting medium. A U-shaped pipe or a similar conduit is utilized to channel the fish tank’s water into the bucket. The water is then drained persistently back into the tank, allowing the nutrients present to be replenished.
Tomatoes grown in an aquaponic system with sufficient nutrients and exposure to light can have twice the growth rate as those grown in a soil-based outdoor farm. Within a span of only 4 weeks, the tomato plants can fully develop and fruit. Managing your growing space creatively to maximize production of cherry tomatoes can turn out to be a lucrative venture.
is a green leafy vegetable that belongs to the family Amaranthaceae. It is commonly eaten cooked or raw, and is a good source of vitamins and minerals. Spinach, a member of the Amaranthaceae family, is a nutritious leafy green vegetable that can be consumed either cooked or raw. It is high in essential vitamins and minerals.
Due to its richness in vitamins, spinach is recognized as a superfood. It stands out as a great crop for aquaponic systems due to its easy upkeep and moderate nutrient needs. Even under varied growth conditions, it yields nutritious foliage with ease, but for palatable leaves, mild temperatures are ideal. Bolting, which causes bitter leaves, may result from warmer temperatures.
The intriguing fact is that the nutritional content of spinach leaves may be affected indirectly by the components present in fish food. Furthermore, the rate of their growth can be enhanced by an increase in trace elements contained in amino acids. While fish food may not cater to all the nutrients essential for the best plant growth, it can potentially be enriched with advantageous trace minerals, particularly those that are beneficial to the health of fishes.
With its various forms available for sale, such as fresh, canned, pureed, and frozen, spinach poses significant potential as a crop suitable for mass production. Fresh spinach leaves are typically regarded as the most desirable and consumable version of this plant. Consequently, organically-grown, premium quality leaves cultivated in an aquaponic setup can command a desirable price. Additionally, as spinach has short roots and can be kept compact, it does not require a lot of space to cultivate.
Brassica oleracea, commonly known as kale, is a type of vegetable.
Over the last 2 decades, kale became vastly popular as a superfood all around the world. This tart and leafy vegetable is a hardy annual that can thrive in cool temperatures. In fact, its leaves become significantly sweeter after exposure to frosts. Due to its tolerance for the cold, it is ideal for aquaponic systems that are subject to ever-changing, temperate conditions.
Many types of freshwater fish thrive in kale’s preferred pH range of 6.5 – 7. Optimal leaf growth is achieved through mild temperatures and partial to filtered exposure to sunlight. Kale leaves provide valuable insights into nutrient deficiencies, making it an excellent choice for understanding the needs of leafy plants.
Nasturtium officinale, also known as watercress.
Watercress was among the vegetables that were initially farmed in aquaponic systems, and it has a long history that spans several millennia. In ancient Asia, people started cultivating this plant on rafts that were floated on fish ponds. Presently, it’s frequently integrated into “polyponic” setups that accommodate numerous kinds of plants, fish, and macroalgae in one system.
Watercress has long been considered one of the most suitable plant species for beginners who want to venture into aquaponics. It is an aquatic plant that can thrive in shallow water, with roots that have evolved to easily absorb nutrients in the water. Moreover, propagating this plant is effortless through divisions. For optimal leaf and shoot yield, cultivating watercress on floating rafts is recommended.
8) Allium schoenoprasum is commonly referred to as chives.
Chives, which require minimal space and can be grown hydroponically, are among the simplest herbs to cultivate. Because it is a perennial, it may be harvested at regular intervals to ensure a continuous flow of tasty leaves. It is able to grow in both indoor and outdoor aquaponic systems, and is chilly-resistant. When given a consistent flow of water that is rich in nutrients and has pH levels in the 6.1-6.8 range, it thrives.
To grow A. schoenoprasum successfully, it is important to place it in a location that receives at least 12 hours of sunlight daily. This can be challenging in temperate areas, and the use of full-spectrum LED lights may be necessary. However, once the roots are established, new leaves can grow quickly.
Chives, unlike most of their onion family counterparts, do not yield subterranean bulbs; instead, their leaves are of commercial significance. This makes it easier to maintain high-quality standards since their leaves can be continuously monitored during the growth phase. When they are established in potting substrates and grown in floating rafts, they can grow at twice the rate of soil-grown plants.
