What could be better than using a water-based hydroponic gardening system to grow vegetables? Well, how about having fish take care of most of the work for you? That’s right, aquaponics involves creating a gardening system where fish live their normal lives – eating, pooping, and swimming – in a tank or man-made pond. The waste produced by the fish serves as a natural fertilizer for plants that are grown in water without soil. To provide a more technical definition, let’s turn to the Natural Agricultural Library. According to the U.S. Department of Agriculture, aquaponics is the combination of fish and plant production (aquaculture) with hydroponics, which is the practice of growing plants without soil.
According to the Permaculture Research Institute, there exists a symbiotic relationship in the system. The plants receive nourishment from the fish, resulting in their strong and abundant growth. The plants subsequently purify the water in order to maintain the fish’s health. Beneficial bacteria, also referred to as microbes, form the third component of this symbiotic triangle. They assist in feeding the plants by converting fish waste (ammonia) into substances (nitrates) that can be absorbed by the plants (according to Eartheasy). Continue reading to acquire comprehensive knowledge about this gardening system.
How is aquaponic gardening different than hydroponic gardening?
Although they may appear quite alike at first, it is evident that there is an underlying issue with the two systems. Ultimately, the main distinction between hydroponic and aquaponic gardening lies in the involvement of fish. The process of hydroponics involves humans actively creating nutrient and fertilizer-enriched water to facilitate plant growth. On the other hand, aquaponics depends on fish to perform the fertilization task through excrement. It relies on the natural balance provided by nature to ensure proper nutrition, as stated by Trees.com.
There are simple methods to create a hydroponic garden, but setting up an aquaponic system becomes more intricate; as you are no longer solely cultivating vegetables, but also raising fish. Oh, the duty! Whether you follow a pescatarian diet and intend to consume the fish you cultivate, or you are a vegetarian determined to provide them a fulfilling life until their natural end, it is crucial to consider the increased responsibility and commitment involved in this form of fish-oriented gardening.
Aquaponic systems are additionally different from hydroponic systems in their greater water efficiency. This is mainly due to the extended utilization of water. In hydroponic setups, the entire water supply must be renewed every three months, whereas in aquaponic setups, this renewal only needs to occur once annually.
History of aquaponics
The practice of aquaponics has a historical record dating back to China in 500 B.C., when a politician named Fan Lee documented it in a study called “The Chinese Fish Culture Classic.” Additionally, anthropological research indicates that around 2000 B.C., several cultures, including China, Egypt, Japan, Peru, Greece, and the Aztecs, were utilizing aquaculture and hydroponics together for sustenance, according to the University of Washington.
In the 12th century A.D., Chinese farmers were focused on finding optimal methods for controlling diseases, designing their ponds, and determining the appropriate number of fish for their systems. Meanwhile, in Mexico, the Aztecs were experimenting with artificial islands called chinampas. These islands were created by enclosing a section of a shallow lake bed and layering it with mud, sediment, and decaying plants to create a floating raft. The top of a chinampa would typically be around a meter above the lake’s surface. Each island would grow crops such as corn, beans, squash, chili peppers, tomatoes, and more, with the roots reaching down into the water. The lake’s natural ecosystem provided the necessary fertilization, and the harvested food was used to feed the people of Tenochtitlán. The practice of aquaponic farming subsequently spread to Indonesia, Malaysia, Thailand, and other regions during the 1400s.
Is aquaponic gardening right for you?
Aquaponic farming, an ancient system that could be ideal for those living in areas with nutrient-deficient or poor-quality soil or lacking yard space, may not seamlessly fit into a modern lifestyle. Environment.co notes that energy costs to operate the filtration system can significantly increase. While those using renewable energy sources such as solar panels may not encounter any problems, those dependent on the electric company could face rapidly accumulating costs.
Although the fish handle the task of nourishing the plants, it is necessary to consistently care for the system itself. It should not be assumed that after setting it up, one can simply leave and come back weeks later to find a thriving vegetable garden. The Permaculture Research Institute cautions that despite these gardens resembling natural ecosystems, they are actually human-created and necessitate maintenance from us. Wholeheartedly engaging in this venture demands dedicating a portion of time every day.
First, after going through the process, you may come to realize that the ritual of burying your hands into the soil and taking in the strong scent of the earth is what you enjoy most about gardening. Becoming a gardener for this very reason is quite rewarding. However, let’s now consider the alternative experience you’ll have when dealing with aquaponic crops – the fishy aroma of recirculating pond water. We don’t intend to discourage you, but in order to determine if aquaponic gardening is suitable for you, it’s important to comprehend the necessary space and water requirements, as well as the equipment involved.
Space requirements for aquaponic gardening
No matter the amount of space you have, whether it be as small as a $15 jar with a betta fish and a plant on the kitchen counter, or as large as a 200-gallon fish tank with a 4-foot by 8-foot grow bed costing $8,500, there is an aquaponic system suitable for you.
According to Gardential, the amount of space your system requires depends on the type and quantity of growth you desire. It is important to ensure that the size of your fish tank corresponds to the size of your grow bed(s). Additionally, the size of the fish should be appropriate for the tank; a small desktop aquarium cannot accommodate a 5-pound Nile tilapia, for example. Gardential suggests two methods to determine the ideal fish-to-water ratio. For ornamental fish, allocate 5 gallons of water per fish. If you are raising fish as a food source, adjust the ratio to 1 pound of fish for every 3 gallons of tank space/water.
To increase the likelihood of success, How To Aquaponic advises ensuring that the area is easily reachable and receives ample natural sunlight. Additionally, it is important to have direct access to both a water source and electricity. It is strongly advised not to connect extension cords together, especially due to the potential dangers of combining electricity and water, which can result in shocks or even worse consequences.
Water requirements for aquaponic gardening
Aquaponic farming setups are also referred to as recirculating aquaculture systems or RAS. Due to their closed loop structure, the water within is continuously purified and reused, making it an extremely sustainable farming method that utilizes only 10% or less of the water required in traditional agricultural operations. Additionally, RAS eliminates the presence of polluted wastewater commonly found in soil-based farms.
The perception of a large amount of water in the tank may make it appear like more than the usual amount that comes out of your irrigation hoses, but in reality, it is significantly less. Symbi Biological has calculated the amount of water needed to grow one head of lettuce in an RAS system (2 gallons) compared to a field (16 gallons). When multiplied by the actual production of 300 lettuce heads, these figures increase to 600 gallons for the aquaponics system and 4,224 gallons for growing the same amount of lettuce in soil. Suddenly, the significant disparity in water usage becomes apparent.
Food & Water Watch points out that while you’re growing vegetables with significantly less water, you’re also simultaneously cultivating a fish harvest. What soil-based gardener can rival that? The use of a recirculating water system within an aquaponic setup results in a pristine and environmentally sustainable setting.
Equipment requirements for aquaponic gardening
The requirements for equipment will depend on the size of your system. Beginning with the fish tank, which is absolutely necessary for aquaponics, you will also need a water pump, an air pump, and PVC piping with fittings. It is possible for advanced DIYers to construct their own tank, but this would require a significant amount of time. For new DIYers who want to avoid mistakes, we recommend focusing on acquiring the necessary equipment. How To Aquaponic recommends buying or finding a non-toxic, food-grade intermediate bulk container, also known as an IBC tote, from secondhand websites.
When it comes to growing plants, you will require a grow bed along with growing media, Rockwool seed starting cubes, and a seed starting tray, according to Farming Aquaponics. In this aspect, there are various options available, and gaining some knowledge will be beneficial. A growing medium serves as a substitute for soil, providing protection and structural support for plant roots. Both organic and synthetic alternatives are available, such as clay pebbles, lava rocks, expanded shale, and coconut coir. Although clay pebbles are considered the best choice, they are not the most economical. Eventually, your decisions will be based on your budget, the type of plants you aim to grow, and personal preferences. Additionally, a water testing kit is necessary for managing pH levels (further details below). To aid you in this process, How To Aquaponic suggests the use of an electrical conductivity (EC) or total dissolved salts (TDS) meter, as well as uniseals, bulkheads, and a siphon.
What plants should you grow in your aquaponic garden?
Apart from leafy vegetables, what other plants can be grown in aquaponics? Whether you prefer to cultivate vegetables or flowers, there is a diverse selection of plants that are well-suited for aquaponic systems. According to How To Aquaponic, tomatoes and cucumbers are highly recommended, but most common vegetables found in traditional backyard gardens will thrive in this type of gardening. Additionally, herbs such as ginger and basil, along with peppers, onions, beets, chard, orchids, and many more, are excellent options.
When considering plants in an aquaponic system, you may need to decide which ones you don’t want an excessive amount of and focus on growing only one type. Having limited pantry space for jars of spaghetti sauce, it is important to consider the plants that grow faster and offer a higher yield of fruits and vegetables. In particular, mint is notorious for its rapid growth, eventually overpowering and inhibiting the growth of other plants. A farmer shared their struggle with containing their mint crop on the Backyard Aquaponics forum, mentioning they plan to remove the roots and burn them. Take this as a word of caution!
Not everyone will appreciate the aquaponic lifestyle, as certain plants have specific pH requirements that may be challenging to maintain in an aquaponic system. According to How To Aquaponic, examples of such plants are blueberries, which prefer a low pH, and chrysanthemums, which require a high pH. Now, let’s delve into the significance of pH.
Aquaponics: Designing and Installation
Aquaponics is the combination of two systems, which allows for its versatility in being tailored to meet the specific needs of individual clients.
- Aquaculture: This aspect fosters fish growth.
- Hydroponics: This element supports plant growth.
An aquaponics system consists of a fish tank at its core, which collaborates with a filter system composed of five main components. These components work together harmoniously to enable the growth of both fish and vegetables.
The rearing tank is where fish are fed and grown. Various materials, such as silipolin lining, IBC tanks, HDPE potable tanks, or natural ponds, can be used to construct these tanks. Typically, these tanks have a minimum depth of 1.2 to 2 meters.
The settling tank is created to gather waste and leftover food, as well as aiding in cleaning by using a biofilter. It can be made using materials such as Ferro cement, IBC tanks, and HDPE potable tanks, and should have provisions for waste disposal.
The biofilter is the place where beneficial bacteria flourish, changing ammonia into nitrates, which then provide nourishment for the plants. Fiberglass, HDPE drums, IBC tanks, and other appropriate materials can be used to construct biofilters.
4) The hydroponics tank is where plants thrive by absorbing nutrients from the water. Similar to rearing tanks, hydroponics tanks can be constructed using materials like silipolin lining, IBC tanks, or HDPE potable tanks.
A sump is created at the lowest point in the system to act as a pit, allowing water to pass through and go back to the rearing tank. Various materials such as pond liners, IBC tanks, HDPE potable tanks, or other suitable materials can be used to construct it.
The concept of aquaponics can be traced back to ancient times, specifically to 1000 A.D. when the Aztecs made references to it. The Chinese also practiced a similar form of aquaponics by growing rice on wooden rafts filled with mud. However, modern aquaponics, as we know it today, was researched and developed in the 1980s.
Previously, the process of growing fish necessitated large areas and lengthy timeframes for harvesting. Nonetheless, the fishing industry has undergone a transformation with the advent of modern fisheries, enabling significant fish growth in a mere six months. Fish in these systems can increase their weight by 350 to 500 grams during this period.
Below is a sample calculation for an aquaponics system, considering each step.
In order to minimize the risk of diseases and stock loss, a targeted stocking density of 25 kg at harvest time is recommended for a 1000-litre tank, which can comfortably accommodate up to 50 fish seeds. It is crucial to maintain the water’s pH level between 6.5 to 7.2 to ensure the healthy growth of both fish and vegetables.
Maintaining proper pH levels in your aquaponic garden
Water quality is a critical factor in aquaponic gardening that cannot be disregarded as it is vital for maintaining the well-being of your fish. According to New Mexico State University, the quality of your water is influenced by its source, whether it is from a well, municipality, or surface water. For instance, regular tap water retains chlorine, which needs to be removed through filtration before it can be employed for farming purposes.
According to World Water Reserve, determining the pH of your water involves assessing the concentration of hydrogen ions, which indicates if the water is neutral (7), basic (higher than 7), or acidic (lower than 7). These pH levels can impact various aspects, such as the fish’s well-being, the plant’s nutrient absorption capability, and even the function of bacteria. To determine the ideal pH range for your system, you must comprehend your fish’s requirements. Typically, this range tends to be alkaline (basic) and falls between 6.5 and 9.0, although it depends on whether you have freshwater or saltwater fish. Additionally, bacteria prefer to reside on the slightly alkaline side of the pH scale.
Plants generally flourish in a slightly acidic setting. Thus, when the three entities coexist symbiotically, the ideal pH range minimizes and falls between 6.5 to 7.5, ensuring everyone’s contentment. To sustain these levels, it is necessary to routinely examine the water utilizing a pH kit. According to Go Green Aquaponics, there are multiple methods to incrementally alter the pH, be it upwards or downwards, in case of necessity. It is crucial to execute these adjustments gradually, in order to avoid shocking or potentially damaging the fish.
Best practices for aquaponic gardening
The Food and Agriculture Organization of the United Nations (FAO) provides key guidelines for maintaining a successful aquaponic system. To start, it is important to carefully choose a fish tank. Fiberglass and inert plastics like Polyethylene and Polypropylene are recommended by Filson Filters as they do not corrode. According to FAO, circular tanks are easier to clean.
To ensure the well-being of fish, bacteria, and plants, it is necessary for the water to contain dissolved oxygen and be in constant motion. This is because the water acts like the lungs of the system, and just like humans rely on air, everything living within the system relies on high-quality water. Therefore, it is essential to have air pumps for proper aeration and water pumps for circulation. The FAO identifies several key factors to monitor for water quality, including dissolved oxygen, pH levels, temperature, total nitrogen, and water alkalinity.
To avoid excessive fish, ensure that you limit the quantity to a manageable number. Whenever you notice uneaten fish food waste, make sure to remove it from the water to prevent it from decomposing and harming the overall ecosystem. Additionally, reduce the amount of food you distribute the following day. Lastly, plan the layout of your grow beds similarly to how you would plan your backyard garden. Conduct thorough research to determine which vegetables are compatible when planted nearby and take into account the time each crop requires for seeding, germination, and reaching harvest. The FAO acknowledges the significance of consistently having a stock of young fish and young plants available.
