Aquaponics mimics a natural ecosystem on a smaller scale, utilizing the same process that occurs in aquatic environments. The fish in this system play a significant role by consuming and excreting waste, which produces nutrient-rich water. Bacteria then convert this waste into fertilizer that promotes plant growth. The plants use the fertilizer and also purify the water, which can be recycled for fish farming. This cycle repeats continuously.
An aquaponics system operates through the symbiotic relationship of fish, plants, and bacteria, resulting in the production of both fish and vegetables with the same amount of water required for obtaining only one product. This process creates a closed cycle, virtually eliminating wastewater released into the environment and preventing water waste.
Aquaponics, Past and Present
Aquaponics has been around for a long time, with its earliest forms dating back 1,500 years ago in South China, Indonesia, and Thailand. During this time, farmers utilized paddy fields, which were flooded with water and contained fish. This combination allowed the farmers to grow rice while using the fish waste as a natural fertilizer.
Another type of aquaponics was developed by a population in central Mexico 500 years later. The Aztecs were a powerful empire with their capital, Tenochtitlán, situated on the shores of Lake Texcoco. The wetland surroundings lacked fertile land for agriculture, so the Aztecs constructed floating gardens called chinampas using mud and dried plant residue. A variety of crops like maize, squash, tomatoes, were grown on these islands and were able to obtain nutrients from the lake water, which had high concentrations of fish feces.
While the concept of aquaponics has been around for a long time, its potential was not recognized until the 1970s when scientists rediscovered it. Currently, aquaponics is becoming more sophisticated and offers an environmentally-friendly solution for agriculture that can reduce the consumption of natural resources. Compared to traditional agriculture, aquaponics requires up to 90% less water and facilitates faster plant growth. Additionally, it helps to minimize pollutants caused by tractors and field chemicals.
Aquaponics systems have the versatility to be set up in both outdoor and indoor environments resembling greenhouses. The advantages of indoor systems include the ability to generate crops all year round, especially beneficial in regions with unfavourable atmospheric conditions like cold temperatures, low daylight hours and scarce rainfall or access to freshwater for irrigation.
Types of Aquaponics
Currently, three main types of aquaponics systems are widely used. Firstly, the raft aquaponics system involves plants placed in drilled holes within floating rafts that are situated in tanks filled with wastewater from fish culture. The roots of the plants absorb nutrients from the water. This type of system is perfect for small plants such as spinach, chard, basil, salad greens, and others. Secondly, the substrate aquaponics system entails placing plants in holes drilled in pipes, which receive continuous flow of fish effluent water. In this setup, plants grow in a soil-mimicking substrate that sustains their roots and enables bacteria to filter the water. This system is suitable for all plant types, with cabbage, onions, cucumbers, peas, broccoli, tomatoes, fennel, beans, squash, melons being the most commonly grown. Lastly, the channel aquaponics system involves plants grown in a soil-mimicking substrate that contains bacteria helping to uptake nutrients from fish wastewater. The wastewater flows through narrow pipes with holes that plants are placed into to support their roots for nutrient absorption. This method is best for plants requiring minimal support, including leafy greens, herbs, and strawberries, and vertical pipes are used to conserve space.
Backyard Aquaponics
What is defined as backyard aquaponics? It’s an outdoor variant of an aquaponic system, generally constructed at home. These backyard systems are designed to have a tank and a growing bed that operate in a straightforward cycle: the fish excrete nutritious waste that nourishes the plants, and the plants purify the water ensuring the fish’s good health.
Backyard Aquaponics Explained: The Basics
The concept of backyard aquaponics is quite simple; worms or microbes convert fish waste into nutrients for plants, and the plants cleanse the water. This mutually beneficial structure creates a continuous loop that leads to the production of nutritious organic plants and fish.
How Aquaponics Works, Basic Setup & System Components
Aquaponics differs from traditional hydroponics as it uses fish to generate nutrients for plants, removing the need for gardeners to manually add liquid supplements. Additionally, plants function as the primary purifier of water in aquaponics, replacing costly water filters commonly used in other hydroponic systems.
Setting up the aquaponic system is quite easy and straightforward.
- A tank is prepared for the fish to live in and create waste
- An air pump and air stone(s) aerate the water
- A water pump forces water, nutrients, and air to a growing bed with plants
- Plant roots anchored in a growing medium soak up the water, air, and nutrients
- A drain pipe gravity feeds the water back into the fish tank
- The cycle repeats itself perpetually
The essential elements for aquaponics include:
Aquarium
One of the two primary vessels employed in aquaponic systems is the fish tank, which must have adequate capacity to accommodate multiple fish. It should be noted that for each plant you intend to cultivate, you must have a minimum of one fish.
Pump that moves water.
In aquaponic systems, there are generally two primary pumps, and the water pump is one of them. The purpose of the water pump is to transfer water from the fish tank to the grow bed, and it ought to be capable of pushing water upwards and out of the fish tank.
Bed used for growing plants.
The second container utilized in aquaponics is the grow bed, which houses the growing medium, plants, and the bulkhead responsible for linking the drain pipe that directs the water back into the fish tank.
Media used for growing.
The grow bed is filled with a growing medium, which usually comprises clay pellets, lava rock, or gravel, and serves as a support system for the roots of plants in the system.
Reworded: Device for pumping air
The air pump, which is the second pump employed in aquaponic setups, links an air hose to air stones for the purpose of providing aeration to the water in the fish tank.
The object being referred to is an Air Stone.
An air tube connects the air stone to the air pump, which adds oxygen to the water for the benefit of both fish and plants.
Tubes or pipes
Usually, PVC is the material of choice for the pipes or tubes used in aquaponics, although vinyl or rubber are used in some instances. These tubes connect to the water pump and serve as a pathway for water to move from the fish tank to the grow bed and as a means of drainage from the grow bed back to the fish tank.
Seals or Bulkheads
The connectors known as bulkheads are inserted either at the bottom or side of the grow bed. After passing through the growing medium, water provides necessary air and nutrients to the plant roots, and then exits through the bulkheads to the drainage tube or pipe.
Aquaponic Methods for the Home Gardener
There are three popular and effective aquaponic methods for home gardeners, but the possibilities of backyard aquaponics are limitless with the use of your imagination.
- Media Bed. The media bed aquaponics method is the most basic and is commonly used for backyard aquaponics. In this system, a grow bed filled with media and plants sits on top of the fish tank.
- DWC. Deepwater culture, or DWC, is another extremely popular form of backyard aquaponics. In this method, the fish tank has a lid on top with grow sites filled with growing media and plants.
- NFT. The nutrient film technique, or NFT, is an effective but somewhat more complex type of aquaponics system. NFT works similarly to media bed systems, except it involves grow pipes with a constant trickle of water flowing through them rather than a bed that’s flooded and drained.
IBC Tank for Backyard Aquaponics
Intermediate bulk container, abbreviated as IBC, refers to the large water storage containers that hold hundreds of gallons of water. Typically, such tanks are enclosed in metal cages, making them the most frequently utilized containers for IBCs.
Frequently, this approach is known as an aquaponics system that involves “chop and flip.”
Setting Up An IBC Tank
Establishing an IBC tank for backyard aquaponics is a relatively straightforward process, but it will require the use of a power saw.
Initiate the process by determining the desired size of the media bed and indicating the appropriate height on the cage. This will serve as the foundation for the media bed. Then, employ power tools to slice through the cage, detach it, and position it upside down on the side.
After removing the cage, saw the top of the tank to the same size as the removed cage. Then, invert it and insert it into the empty section of the cage. This will finalize your media bed and support.
The cage ought to exceed the media bed by at least two times, however, it is recommended to have it around three times bigger. In some cases, it could even be as much as four to five times larger than the media bed.
Clean both the tank and media bed meticulously and position them accordingly. Place the media bed horizontally over the tank and proceed to install all fundamental parts.
Install a water pump which is capable of submersion in the fish tank, and an air stone that links to an external air pump. Connect a pipe or tube between the outlet of the water pump and the top of the media bed.
To set up the system, affix a bulkhead or a low-side seal onto the media bed, and attach a small PVC drain pipe that empties into the fish tank. Then, place the growing medium in the grow bed, introduce water and fish in the tank, and plant your desired vegetation in the growing medium.
Pros
Utilizing the IBC tank method is an excellent choice for both commercial enterprises and large-scale backyard aquaponics as it allows for the growth of a greater quantity of fish and plants. Moreover, this method involves a single tank that is partitioned into two sections.
Cons
Compared to conventional fish tank setups, IBC systems require a greater investment of time and effort for installation. In addition, they are more costly as IBC containers are pricier than the typical backyard aquaponics materials of totes, wooden frames with plastic liners, or fish tanks.
Nutrient Film Technique (NFT) for Backyard Aquaponics
The NFT technique is a highly favored method of implementing aquaponics in one’s backyard. Under this method, a tank serves the purpose of housing fish, while a series of pipes, and net pots within them, hold and secure the plants.
The system features a constant and thin water flow, referred to as the “film,” which is circulated by an air pump, air stone, and water pump.
Setup
To construct an NFT structure, first acquire a water tank for fish, a submersible water pump, and an air stone. Then, place the air pump with an attached air hose adjacent to the tank. The waterproof container may consist of a barrel, sizable tote, wooden crate coated with plastic, or another appropriate option.
Afterward, make a decision on how you would like to position your cultivation pipes. The optimal method involves placing them one on top of the other in a vertical manner. The majority of setups involve three to four distinct pipes at a minimum.
To indicate where you want to create each grow site, make use of a measuring tape and a marker. A simple technique is to follow the outline of your net pots. For smaller leafy greens, position your grow sites only a few inches away from each other, but for larger plants like tomatoes or melons, maintain a distance of 18 or 24 inches.
Once you have set up your growing locations, drill a single hole in each PVC end cap. One end cap of each tube should have a high hole, while the other should have a low hole, enabling the water pump and gravity to perform their respective tasks.
After drilling the holes, fit pipe fittings into them to enable connection of a water pipe tube and smaller tubes with elbows running from one grow pipe to another, serving as drains.
Attach a PVC tube or vinyl hose from the fish tank to the topmost grow pipes. Upon being pumped up, water will percolate through all the grow pipes in the setup, passing every grow site as it descends.
After a while, the water returns to the fish tank and goes through the entire system once more.
Pros
The NFT boasts water efficiency by constantly recirculating water and minimizing evaporation. Additionally, this aquaponic system is particularly space-saving, often being stackable and possessing a slender profile. NFT also proves to be an economical option for those who elect to construct their own system.
Cons
Constructing an NFT system entails more time and effort than other methods, and also necessitates familiarity with tools and plumbing components. Moreover, NFT has a substantial learning curve and may not be optimal for larger plants.
