The concern about traditional agriculture's impact on land, water, and resources has led to a surge in interest in sustainable farming methods. Aquaponics is seen as a highly efficient farming solution that addresses these multiple farming challenges. By using less water compared to conventional farming, reducing the need for synthetic fertilizers, and minimizing waste, aquaponics presents a promise for producing food without damaging our environment.
This article will delve into aquaponics and provide a comprehensive understanding of how it works its principles, benefits, and potential challenges. Through this article, readers will gain insight into what aquaponic is, how it works, and why this method of growing holds promise for revolutionizing modern agriculture.
What is Aquaponics?
Aquaponics is a sustainable farming method that combines aquaculture (the cultivation of aquatic organisms like fish) with hydroponics (the growing of plants in nutrient-rich water without soil). This combination creates biological processes that occur in both systems to create a closed-loop environment where fish and plants thrive together.
How Does Aquaponics Work?
In aquaponics, the plants are grown in the grow bed, and fish are placed in the fish tank. The nutrient-rich water from the fish tank that contains fish waste is fed to the grow bed, where billions of naturally occurring beneficial bacteria break the ammonia down into nitrites and then into nitrates.
Plants absorb these nitrates and other nutrients to help them grow. The plant's roots clean and filter the water before it flows back into the fish tank for the fish to live. The fresh, clean, and oxygenated water recirculates back to the fish tank, where the cycle will begin again.
1.The Nitrogen Cycle
- Explanation of the Nitrogen Cycle: In aquaponics, the nitrogen cycle is a fundamental process that transforms toxic ammonia from fish waste into less harmful nitrates. Fish excretes ammonia that accumulates in the water. Beneficial bacteria, specifically Nitrosomonas, convert ammonia into nitrites. Another type of beneficial bacteria, Nitrobacter, then converts nitrites into nitrates that serve as a valuable nutrient source for plants.
- Role of Beneficial Bacteria in Converting Waste: The presence of beneficial bacteria is essential for the nitrogen cycle to function. These bacteria colonize the surfaces of the grow beds and grow media, providing a substrate for their growth. Without these bacteria, the toxic ammonia produced by fish waste would accumulate and harm the fish. This is why the conversion of ammonia and nitrites into nitrates is essential to the aquaponics systems.
2.Fish and Plant Symbiosis
- Fish Waste as a Nutrient Source: Fish excrete waste that contains ammonia, a nitrogen-rich compound. Excessive ammonia levels can be harmful to fish, but this waste becomes a valuable resource for plant growth in aquaponics.
- Nutrient Absorption by Plants: As water from the fish tanks flows into the grow beds or PVC pipes plants absorb the nitrates through their root systems. These nitrates provide essential nutrients like nitrogen and phosphorus that promotes plant growth and development.
- Purified Water Returning to the Fish Tanks: The plants' uptake of nutrients fuels their growth and naturally filters the water. Purified water, now clean of excessive nitrates and other waste, is then recirculated back into the fish tanks, creating a closed-loop system.
The History of Aquaponics
Aquaponics can be traced back to the Aztec Indians around 1000 AD, who grew plants on rafts on the surface of Lake Texcoco. While the Aztec chinampas in Mexico are believed to be the basis of modern aquaponics, the people from eastern Asia (China, Indonesia, and Thailand) were also thought to be among the earliest aquaponics practitioners.
In Asia, farming involved growing rice in paddy rice fields with the help of fish such as catfish. The wastewater from the catfish tanks was used to fertilize the rice fields and other crops.
While the ancient people of Asia and Central America produced the concept of growing plants and fish together, the existence of modern aquaponics that is getting popular these days started in the 1970s. The development of modern aquaponics is attributed to the works of the New Alchemy Institute and North Carolina State University by Dr. Mark McMurtry.
The New Alchemy Institute researches the creation of ecologically derived human support systems for renewable energy, aquaculture agriculture, landscapes, and housing.
Part of the research was focused on aquaculture, where they experimented with raising edible fish in above-ground tanks. The fertile waste water from the tanks is then used to feed the crops in the greenhouse.
Dr. McMurtry was inspired by the works of the New Alchemy Institute and started research on aquaponics. In the mid-1980s, with Prof. Doug Sanderson, the first closed-loop aquaponics system was created.
In their aquaponics system, the wastewater from the fish tank was used to irrigate crops such as cucumbers and tomatoes in the grow bed filled with sands. The sand served as the bio-filter of the water that passes through it. The water then returns to the fish tank filtered by the sands.
Components of an Aquaponics System
A. Main Components:
To achieve maximum growth output from your fish, select the best fishfor your system and know how to care for the fish in your system correctly.
What Fish Species are Best for Aquaponics?
The most common fish raised in aquaponics systems are:
- Edible fish: tilapia, carp, catfish, trout, largemouth bass, salmon, yellow perch, bluegill, jade perch, barramundi
- Ornamental fish: goldfish, koi, tetras, guppies
- Other aquatic animals, such as shrimps
Where To Buy Live Fish?
You can purchase fish fingerlings online or visit your local pet or fish store to see if they sell fish fingerlings. In buying fish fingerlings online, make sure that you are buying from a credible online aquaponics store like gogreenaquaponics.com to ensure your fingerlings are high-quality, chemical-free, and will arrive alive at your location.
Choosing the best plants to grow in your aquaponics system is essential for your system's overall success. So select plants that are easy to grow and well suited to your location.
Until your new system is fully established, avoid planting nutrient-hungry plants like tomatoes and stick to easy-to-grow plants like leafy greens, lettuce, and herbs. Nutrient-hungry plants require a lot of nutrients, so wait until the fish in the system is larger before adding tomatoes, peppers, and other fruit-bearing plants.
Plants in Aquaponics are planted in the grow bed, pipes, or floating rafts. If you're using grow beds, ensure the grow bed container is strong and the grow medium is deep enough to hold your plants.
When planting your plants, ensure that the base with the plants is sturdy enough to keep them when they grow. Net pots are recommended because they allow the plant roots to absorb nutrients while securely holding the plants. If you're planting in a floating foam, make sure it is lightweight, buoyant, and can hold the plants upright.
What Type of Plants Can You Grow in Aquaponics?
Almost all plants can be grown in aquaponics. However, plants also have different nutrient, space, and light requirements. So, to choose the best plants and achieve the optimum result from your aquaponic system, consider the factors mentioned above.
Here is the list of plants that grow best on a specific aquaponics method:
- Media Based Aquaponics System: lettuce, tomatoes, ginger, eggplant, cucumber, and any plants that will fit your grow bed.
- Raft System: lettuce, basil, kale, cabbage, Swiss chard, bok choy, mint, watercress, and other small rooting plants
- Nutrient Film Technique (NFT): lettuce, strawberry, spinach, parsley, dill, and other small rooting plants.
Where to Buy Seeds?
You can purchase seeds onlineor visit your gardening supply store. Make sure to follow the instructions that come with the seed packet. Here are our recommended seeds from Amazon.
The bacteria in aquaponics systems can be present in the biofilter, grow beds, and fish tanks. Bacteria convert fish wastes into nutrients absorbed by the plants. So, it is essential to maintain a healthy bacterial colony in your system.
- Fish Tank - The fish tank is the home of your fish and one of the most important materials of the aquaponics system.
- Grow Bed - Will hold your plants and grow media. Depending on your system, the grow bed can be PVC pipes, floating rafts, or any food-grade containers.
- Grow Bed Support - Frame that will support the weight of your grow bed.
- Sump Tank- Optional. Using a sump tank will depend on the design of your system.
- Plumbing Pipes and Fittings - It depends on the type of your grow beds, system, and other factors.
- Bell Siphon - A bell siphon is required for a flood and drains media bed.
- Water Pump - The water pump size depends on your desired tank exchange rate, and several grow beds.
- Aerator and Air Stones - These are used in the fish tank and media beds.
- Grow Lights - Optional. Grow lights are mainly used in indoor systems.
- Heater - Optional. Using a water heater will depend on your location, fish species, and target water temperature.
- Grow Media - You can use clay pebbles, expanded shale, gravel, and other inert grow media for a media-based system.
- Monitoring System - Optional. It depends on your situation and how you want to manage your system.
- Timers and Controllers - These are used for controlling the lighting, pumping, and temperature.
Types of Aquaponics System
There are the four main types of aquaponics systems, which we will discuss below.
1. Media Based Aquaponics System
Media Based, or Flood and Drain is the most common aquaponics system. A media based uses a grow bed or container filled with grow media (usually gravel, lava rock, or clay pebbles) to plant the crops.
Thegrow bed is periodically flooded with water from the fish tank through a bell siphon so that the plants can access the nutrients. The water drains back into the fish tank, where a new cycle begins.
All waste is broken down in the grow bed. Sometimes worms are added to the grow media to help break down all the waste. The media based uses the fewest components, and no additional filtration is needed, making it easy to operate.
2. Raft System
The raft system is also known as Deep Water Culture or Floating System. In a raft system, the nutrient-rich water circulates through the long canals, usually at a depth of about 20 cm, while rafts (polystyrene or foam board) float on top.
The plants are grown on the raft boards supported within holes by net pots. Plant roots hang down in the nutrient-rich, oxygenated water, where they absorb oxygen and nutrients to thrive.
The nutrient-filled water flows continuously from the fish tank through the filtration process, then to the raft tank where the plants are grown, and finally back to the fish tank. Most often, the raft tank is separate from the fish tank.
3. Nutrient Film Technique (NFT)
The Nutrient Film Technique (NFT) is a hydroponic growing technique adapted to aquaponics because of its simple yet effective design that works well in some environments.
In the NFT method, the plants are grown on long, narrow channels. A thin film of water continuously flows down each channel to provide plant roots with water, nutrients, and oxygen.
Like the raft system, the water flows from the fish tank through filtration components, through the NFT channels where plants are grown, and then back into the fish tank. A separate biofilter is required in NFT because there is insufficient surface area for the beneficial bacteria to live.
Benefits and Challenges of Aquaponics
Aquaponics offers a range of compelling benefits, but it also comes with its own set of challenges. These are the benefits and challenges of aquaponics.
A. Benefits of Aquaponics
- Sustainable Food Production: Aquaponics is a sustainable solution to the growing concern of food security. Integrating fish and plant cultivation maximizes resource efficiency while producing protein (fish) and produce (plants) in a single system.
- Year-Round Cultivation: Aquaponics aren't confined by seasonal limitations. With controlled indoor aquaponics systems, crops can be grown year-round, ensuring a steady supply of fresh produce regardless of external weather conditions.
- Minimal Environmental Impact: Traditional farming can contribute to soil erosion, water pollution, and excessive resource consumption. Aquaponics reduces these negative impacts by using less water, minimizing waste, and eliminating the need for synthetic fertilizers and pesticides.
B. Challenges of Aquaponics
- Initial Setup Costs: Establishing an aquaponic system can be costly. Investments are required for components like fish tanks, grow beds, pumps, lighting, and plumbing. While the long-term benefits can outweigh these costs, it's essential to consider the initial financial outlay.
- Technical Knowledge Required: Aquaponics involves understanding complex interactions between fish, plants, bacteria, and water chemistry. A solid understanding of these principles is crucial for the success of the system.
- Potential for System Imbalances: Achieving a harmonious balance between fish, plants, and bacteria can be challenging. Fluctuations in water parameters like pH, ammonia, and nitrate levels can disrupt the balance of the system which can lead to stressed fish or poor plant growth.
Setting Up an Aquaponic System
This section explores the steps involved in setting up an aquaponic system.
1.Choosing the Right Fish
- Suitable Fish Species for Aquaponics: Not all fish species are well-suited for aquaponics. Tilapia, trout, catfish, and perch are commonly used due to their adaptability to the system's conditions. However, when selecting fish, regional factors and local regulations should also be considered.
- Considerations: The chosen fish species should align with the temperature of your location. Consider also the fish's growth rate and waste production. Faster-growing fish might produce more waste, impacting nutrient levels in the system.
2. Selecting the Best Plants
- Types of Plants That Thrive in Aquaponic Systems: Leafy greens like lettuce, herbs, tomatoes, and peppers are popular choices for aquaponic cultivation. These plants have relatively high nutrient requirements, making them compatible with the nutrient-rich water from fish tanks.
- Factors Affecting Plant Selection:Different plants have varying nutrient needs. Consider the nutrient content of your fish waste and how well it matches the plants' requirements. pH levels should also align with your chosen plants. Adequate lighting, whether natural or artificial, is crucial for photosynthesis.
3.Types of Aquaponics Systems
- Design Options: Media beds, nutrient film technique, raft system and hybrid aquaponics systems are the common aquaponics systems designs.
- Components: Tanks, pumps, grow beds, piping. The size of these components will depend on the scale of your aquaponic system.
4.Cycling the System
- Initiating the Nitrogen Cycle: Before adding fish, establish the nitrogen cycle by introducing ammonia into the system. This jump-starts the growth of beneficial bacteria that convert ammonia to nitrites and nitrates.
- Introduction of Fish and Bacteria: Introduce the fish once the nitrogen cycle is established and ammonia and nitrite levels stabilize. Their waste will further fuel the nitrogen cycle. Beneficial bacteria will grow on the surfaces of the grow beds and in the media, converting toxic waste.
- Gradual System Maturation: The system will mature as the bacteria populations increase. Monitor water quality parameters and adjust fish feeding accordingly. Gradually introduce plants to the system, allowing them to acclimate to their new environment.
Tips for Getting Started
Embarking on an aquaponics journey can be exciting yet daunting. Below are tips to help beginners set up their aquaponics systems.
1.Research and Education
Before diving into setting up an aquaponic system, invest time in thorough research and education. Understand the fundamental principles of aquaponics, the nitrogen cycle, the interaction between fish and plants, and the role of beneficial bacteria. Online resources, books, workshops, and community forums can provide valuable insights. Knowledge gained during this phase will form the foundation for successful system management.
While enthusiasm might tempt you to build a large-scale aquaponic system from the start, it's often wiser to begin with a smaller setup. A small-scale system allows you to grasp the intricacies of aquaponics without overwhelming yourself. As you become more comfortable and confident, you can gradually scale up your operation.
3.Patience and Monitoring
Aquaponics is a dynamic ecosystem that requires patience and constant monitoring. Be prepared to observe your system closely, regularly checking water parameters, fish behavior, and plant health. Fluctuations will occur, and adjustments will be necessary. Cultivating patience and a keen eye will help you identify potential issues before they escalate.
Remember that aquaponics is as much an art as it is a science. Trial and error are part of the learning process, and each system has unique characteristics. Embrace the learning curve, adapt your approach based on observations and data, and be open to making improvements over time.
Learning about aquaponics can be challenging, but many free resources are available online if you are interested in learning. You can also read our article, "The Ultimate Aquaponics Beginner's Guide," to learn how to start your own aquaponics garden.