There are people who believe that dreaming big is important, and they are right! But what if that big dream has already been made possible? What if it is possible to grow healthy plants and raise fish in a space as small as your closet? Aquaponics is a method similar to hydroponics, where plants grow in a medium without soil and their roots are constantly kept hydrated. Aquaponics has gained popularity in developing regions of the world because it allows for the production of a variety of plants. Currently, aquaponics is considered one of the most self-sufficient concepts for household farming.
Why Aquaponics?
Aquaponics provide the advantages of water conservation and optimization, just like hydroponics, while also producing fish for human consumption. Aquaponics use only 10% of the water per plant compared to traditional agriculture. The world is currently experiencing severe and frequent droughts, causing crops to wither and leaving farmers without income. Additionally, lakes and rivers are drying up, and conflicts over water usage are becoming more widespread. By feeding goldfish, one can effortlessly supply nutrient-rich water directly to plants, eliminating the risk of excessive irrigation and reducing evaporation rates.
Aquaponic systems of all types and sizes can be found worldwide in areas where they are needed the most because people in developing nations do not have the time to adjust hydroponic systems. Unlike hydroponic systems, aquaponic systems only need to be fed and monitored once a day to yield a protein-rich harvest. Just envision being able to produce a complete meal of fish and salad right in your own closet or balcony.
How does it work?
Aquaponic systems, akin to functioning ecosystems, require plants and fish to coexist in a balanced manner for their survival. Unlike hydroponic systems, which necessitate the addition of nutrient solutions to sustain plants, aquaponics entails a simple task – feeding the fish. If the plants deplete the nutrients produced by the fish, resulting in clear water and healthy plants, then the system is in equilibrium. Conversely, if the water is clear but the plants struggle, it indicates a shortage of waste produced by the fish. Conversely, if the plants appear healthy and the water is murky, it signifies an excessive production of fish waste, which can prove fatal. The Nitrogen Cycle bears the closest resemblance to the ecosystem dynamics in aquaponics. In this cycle, fish in the reservoir consume food, leading to the excretion of ammonia-rich waste. Even low concentrations of ammonia pose a significant threat to fish, and if left unattended, its levels will rise. However, plants can utilize ammonia as a nutrient, bringing equilibrium to the system.
Is it as simple as feeding ammonia to plants? No, it’s not. Ammonia is not a usable form of nitrogen for plants. When fish produce ammonia-rich waste, Nitrosomonas bacteria convert it to nitrite, and then Nitrobacter bacteria convert it to nitrate. Nitrate, which is the least harmful nitrogen form to fish, is then taken in by plants as a potent fertilizer.
Different Systems
Aquaponic gardening can be simplified. Various systems have been created based on the fundamental principles and modified based on the scale, plant requirements, and desired results. To simplify your search, we have provided descriptions of the three most effective systems that we have found to be successful. Additionally, we considered cost-effectiveness when compiling this list.
- Continuous Flow System: The image you most likely have in your head of a system where water is continuously circulating is known as a Continuous Flow System. This system keeps water circulating to roots constantly which allows for an even distribution of nutrients to water-loving plants. Although some of these systems maintain roots completely submerged, the Nutrient Film System is one where root tips are constantly in contact with water without being totally submerged, which saves energy and increases aeration.
- Intermittent Flow: In the quest to both conserve energy and allow plants to keep their roots submerged for most of the time, a system known as Intermittent flow was created. This system is ideal if you do not have your system hooked up to solar, want to conserve energy, and would like to grow plants that rather remain submerged, such as lettuces. The intermittent flow system works on a timer which activates the pump to fill up the grow beds with water from the fish tank every hour. The grow tank then empties itself via permanent drain holes at the bottom which send the water back to the fish tank. This sort of system eliminates the need for a continuous filling pump and continuous draining pump.
- Flood and Drain System: Also commonly used in hydroponics, The Flood and Drain system is known to be a simple system. Aside from the basics, it contains a submersible pump with a timer. The grow tray is flooded with water from the fish tank two to four times a day for approximately 30 minutes each: this equates to 15 minutes of flooding and 15 minutes of draining per cycle. The convenience of this is that water and nutrients can be fine-tuned to achieve optimal plant health and yields. We would remind you that this system needs to be monitored often as a failure to flood on time could leave plants without water for longer than they can survive. Once plants reach the wilting point, there is no turning back.
Living Components of Aquaponics
- Fish: Fish are what set aquaponic farming apart from hydroponics. Although it might seem that hooking up your plants to a goldfish bowl will do the trick, you will also need to take into account the health of the fish in order to yield a healthy meal to eat. Common fish used in aquaponics are tilapia, carp, and catfish. Each fish should be thoroughly researched for specific feeding and breeding habits which will determine differences in management. Tilapia are typically recommended as the best fish for beginners looking to learn through experience, and of course, as a versatile fish consumed in most cultural dishes. In reality, tilapia farming was being done 4,000 years ago by the Egyptians. Conveniently, Tilapia are hardy fish that can withstand failures in the situation of low aeration, higher ammonia, diseases and parasites, changes in temperature, and most other stressors. Given their hardiness, Tilapia can also eat just about anything. Their diet can even be supplemented with kitchen scraps like rice and bread. It is recommended that tilapia be fed 1 pound of tilapia per 10 adult fish up to 4 times a day. Tilapia can also be fed by algae growing in the tank which contains an array of nutrients needed for their healthy development. Tanks left in the sunlight will quickly develop algae which can feed tilapia.
- Plants: Plants are complex organisms that have as vast a range of attributes as they have needs. As any complex organism, plants have cells that are specialized in certain functions, such as structural support, transport of nutrients, making roots, converting light into food, and even breathing! Interesting groups of these cells together usually present themselves as noticeable parts of the plant, such as roots, stems, and flowers.
- Beneficial Bacteria: Beneficial bacteria are also a necessary component of this system but are found naturally in the air and water. They are needed to convert the fish waste ammonia into a form of nitrogen that can be used by the plant. Make sure to not use tap water as it contains chlorine which will inhibit algal growth. Ideally, use rainwater or well water for the aquaponic garden with a booster cup of water from a nearby healthy body of water to introduce an ample amount of beneficial bacteria.
System Considerations
In order to minimize any potential obstacles, it is important to consider certain factors before establishing an aquaponic system in your home.
- Fish out of Water? For starters, float valves should be used in both the fish tank and grow tray to ensure that neither overflows nor is left without water. Imagine the plant tray being full of water for 30 minutes in a Flood and Drain system where fish would be left dry for that same amount of time! This mistake is common for those who have experience in building hydroponics which do allow for reservoirs to go dry. In essence, ensure that the entire system has more water as a whole than is needed in the plant tray.
- Structural Support: Make sure your structure is strong and reinforced! Each gallon of water equates to 8 pounds plus however many pounds of fish you have. It is recommended that the heavier parts of the system be kept lower to the ground.
- To Algae or not to Algae? Although the sun promotes algal growth which tilapia eat, algae can also cause clogs in the filters and tubes which could cause sudden changes for the fish and plants. The smaller the fish tank, the bigger the impact the sun has on water temperature; the inverse is just as true. Such drastic temperature changes could be lethal to fish. The safest bet is to keep your fish tank shaded from sunlight.
- Test Your System! Once you have set up your system, run it for a few days before bringing in new fish. It would be a shame to lose your first group of fish to an easily avoidable technical error. This would also be an ideal time to practice using pH, ammonia, nitrite, and nitrate level tests which should become a habit for your system in order to achieve equilibrium.
Common First Problems
In this section, we will provide an overview of prevalent problems in aquaponics. We will discuss their potential implications and recommended solutions.
- Fish Gulping: Are your fish spending most of their time on the surface gasping for air? This most likely means that there is not enough oxygen in the water. This can be remediated by ensuring your air pump is functional or by making the grow tray outflow water cascade into the fish tank upon escape to promote further aeration.
- Algal Blooms: If water starts to turn red or green with visible algae then you might have an algal bloom. This happens as a result of excess nutrients in the water. You could feed your fish less in order to ensure that no food is going to feed algae. Algal growth on the walls could be a sign of too much sunlight and could be fixed by shading the fish tank.
- Weak Plants? Are your plants looking yellow or weak? If plants are looking deficient in nutrients, it is recommended to use an organic fertilizer such as seaweed extract. Do not use any synthetic fertilizers as they could be very lethal to your fish!
- Nasty Pests: A sign of slugs or snails in the system could be common as they seem to be attracted to places that are constantly wet. If you cannot pick them off and feed them to the fish then it is recommended that you flood and drain the grow tray; this should flush them straight into the mouths of hungry fish.
- Dead Fish: Finding a dead fish in your system could be a sign of a variety of problems. This is usually due to an excess of ammonia which could mean that there are not enough plants and bacteria breaking down the nitrogen in the system. Fish kills could also happen if the water is not properly aerated due to a broken air pump. The most important thing is to remove and dispose of the dead fish immediately.
Should Grow Lights be Left on All the Time?
Q: If I provide my plants with continuous light, will they grow faster? My assumption is that by keeping the lights turned on constantly, they will transform into large plants.
A: It is generally advised not to keep grow lights on continuously. Plants require a cycle of light and darkness for healthy growth. It is believed that during periods of darkness, plants rest and utilize this time to distribute nutrients throughout their entire structure while pausing their growth.
Keep in mind that most plants require at least 12 hours of light per day, at different levels of intensity. Refer to your plant guides to determine the specific sunlight requirements of your hydroponic plants throughout their growth and flowering stages.
By setting up a timer on the lights over your hydroponic garden, it is possible to ensure that your plants always receive the appropriate amount of light. With the assistance of a timer, there is no need to be concerned about remembering to switch the lights off or on.
