What Is Aquaponics? How Does It Work?


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Hydroponics is becoming an increasingly popular method to grow vegetables and plants in water. Aquaponics uses parts of hydroponics and freshwater fish to create a sustainable way to grow plants.

I’ll get more into the details here and answer the base questions of “What is Aquaponics” and “How does Aquaponics work?” in this article. This is more of an aquaponics for beginners that you can always come back to as a refresher. 

Aquaponics can also be a fun way to learn more about growing plants and farming fish with the kids. It can be more fun than learning about traditional soil gardening. It’s a great way to learn more about different innovative gardening methods.

What is Aquaponics and How Does It Work? 

Aquaponics is a combination of aquaculture and hydroponics to grow plants without soil. Let’s first do a quick overview of hydroponics.

In traditional hydroponic systems, plants are grown in a soil-less medium and fed a constant supply of water enriched with nutrients from an organic process. This is a highly efficient way of growing plants that utilize a LED lighting system to act as sunlight and allows crops to be grown all year-round. 

Aquaponic gardens are a hydroponic system with a pretty neat twist. In an aquaponic system, the water and nutrients actually come from a fish tank. The waste products of the aquatic animals in the tank are nutrient providers for the plants.

When balanced correctly, this is a complete self-sustaining ecosystem, in which waste from fish farming methods become the source of rich nutrients for plants. 

Natural and Sustainable Aquaponics Ecosystem

This mimicry of natural aquatic ecosystems is the fundamental base of an aquaponic system. This natural process integration of flora and fauna is found in all natural aqua-ecosystems.

Fish waste output is broken down by bacteria that live within the root systems of the plants. The work done by these microbes is what turns the waste bacteria into nutrients that plants can utilize. This “nitrogen cycle” converts rich ammonia levels from waste into nitrates that the plants can feast on. 

To complete this symbiotic combination, the plants keep the water healthy for the freshwater fish by “cleaning” the tank of waste as they draw the nutrients from the water.

This makes for a highly sustainable method and cycle of growing plants with natural resources and without heavy nutrient input, which has the added benefit of being an engrossing and fun thing to do!

Types of Aquaponic Systems

Most types of hydroponic systems can be used in an aquaponic system. The main difference is the replacement of existing water reservoirs/tanks with a system that provides a suitable habitat for fresh water fish to live in. 

Three common systems that can be used for aquaponics are:

  1. Nutrient Film Technique -- The roots are partially submerged in the water and partially exposed to the air. It is this configuration that makes it unsuitable for plants with larger root masses as this can clog the water channels. This system is better for growing lettuce and other leafy green plants. 
  2. Deep Water Culture -- This system is often referred to as float or raft systems. In this system, plant growth takes place on rafts with the roots suspended into the water. This technique is great for growing larger plants, but because there is no growing media, a more advanced filtration system is required. 
  3. Media Bed –  This type of aquaculture uses medium such as clay or gravel to support the root system of the plant. The bed that the media sits upon is flooded with the nutrient rich water, the water that is drained back into the fish tank has been scrubbed of much of the waste products. 

What Plants and Vegetables Can You Grow in Aquaponics Systems?

Many types of plants, vegetables, fruits, and herbs can be grown in aquaponics, but before deciding what to grow, there are a few factors to consider. Factors include: 

  • The types of systems 
  • The light system, water temperature and water hardness
  • The pH level requirements of both fish and plants
  • The number of fish in the tank

When it comes to water, it’s important to try to match fish and plants together that prefer a similar acidity and temperature environment. 

As I already noted, the type of aquaponic system is also a critical factor when selecting plant types. For NFT systems, for these plant tray systems choose leafy crops like lettuce, kale, watercress, or mint. Other systems are better for growing plants with more complex and thicker root systems. 

Examples of plant species and vegetables that are aquaponic compatible include:

  • Herbs
  • Cabbage
  • Cauliflower
  • Tomatoes
  • Peppers
  • Strawberries
  • Decorative flowers

If you are just starting out with an aquaculture system, it is important to note that these systems take some time to “mature” and get the nutrient levels balanced.

For newer systems it is better to start with quick growing plants that have low nutrient needs. That’s why lettuce is a popular choice when starting out with aquaponics.

Other popular plants that are suitable for growing, before you have the perfect level and balance of nutrients, include cucumber, Swiss chard, and watercress. 

Once your aquaponic system has been running for a while, this could be up to 6 months, then the nutritious fish effluent within the water will be of a high enough level that you can begin to grow plants with higher nutritional needs. 

What are the Best Plants for Aquaponics?

What Types of Fish Can You Grow in Aquaponics?

As I touched upon it is crucial to balance the needs of both the fish and the plants you are growing. To this end, you need to try to match the pH and temperature requirements of both as closely as possible.

While commercial aquaponic farms have a wider range of fish to choose from for fish production, smaller and home aquaponic gardens don’t have as much flexibility. There are still plenty of varieties to choose from though and these are popular fish that help to provide optimum plant growth in aquaponics systems: 

  • Carp and KOI carp
  • Goldfish
  • Tilapia
  • Pacu
  • Catfish
  • Angelfish
  • Guppies
  • Mollies

Factors that go into deciding the types of fresh fish in tanks include the size of the tank, the kinds of plants you intend to grow, the water temperature, and the nutrient dynamics.

Best Fish for Aquaponics

What are the Benefits of Aquaponics?

For the home grower, this indoor agriculture method of producing fresh organic vegetables using the perfect collaboration in which microbes perform a conversion of ammonia from fish waste into the perfect nitrate based fertilizer, has many advantages. 

As well as being good for the environment by utilizing mother nature’s own methods of producing a natural, perfect fertilizer as plant food without the need to completely flush the water reservoir out periodically.

When combined with the proven yield improvements that hydroponics grow systems provide, it can really be the perfect self-sustaining path to providing crop after crop of organic vegetables, free from synthetic fertilizers.  

  • It uses a natural fertilizer source as opposed to using nutrient solution
  • Growing using this method consumes up to 90% less water than traditional agriculture methods
  • Inexpensive fish feed means its cheaper than expensive, man-made nutrients
  • Recirculating aquaculture systems are a sustainable and highly productive method of growing a wide variety of crops
  • Recirculating water reduces water bills and water consumption
  • No herbicides or pesticides required, these are also dangerous for the fish.
  • Food crops can be grown all year round
  • Low energy consumption
  • Higher yields than growing plants in soil

What are the Disadvantages of Aquaponics?

While there are many advantages to growing your plants and fish in an aquaponic system, there are some downsides to aquaponics.

As with any controlled environment agriculture system, you have to maintain a close watch on the overall health of the system. This is particularly the case when you have to consider not just the health of the plants, but of the fish as well.

Other drawbacks include:

  • It is more difficult to set up than a hydroponic system. With hydroponics, you can fill up the reservoir with water, add your nutrient solution, and you are pretty much good to go.
  • With an aquaponic system, achieving the balance of fish waste, bacteria, and high nutrient levels can take time. You don’t want to rush this, so you can avoid diseases in aquaponics gardens.
  • More complicated than hydroponic systems. You are going to need a filtration system, water pump, and aeration to provide the fish with the oxygen they require.
  • More variables to control with plants and fish. If you have an unhealthy environment, fish can get diseases that could hurt plants in these systems. 
  • Higher start up costs due to more equipment needed, as well as the costs for the fish. It’s more expensive to set up an aquaponic system than a typical hydroponics system.
  • Space is needed for the supply of fish stock, variety of plant species, and for a functional garden in general.

Aquaponics System Setup and Management Tips 

Getting your system established is when you’ll be spending the most time on it to monitor. During the first couple of months, before your natural ecosystem has had time to reach maturity, it is crucial that you monitor everything.

Keep an eye on the water quality, water temperature, acidity, and concentrations of ammonia build up. 

Other useful hints and tips include:

  1. Backup power supply. To keep your fish and plants safe, have a backup power supply on standby. Loss of oxygen in the water can quickly result in unhealthy fish.
  2. Never overstock your fish tank. Too many in a tank can be harmful to the fish and let diseases spread easily. Don’t be afraid to remove excess fish should you deem it necessary.
  3. Don’t be overambitious, start small and grow plants that have light nutrient requirements. 
  4. Remember to match the fish and plant requirements as closely as possible. This includes matching the acidity and temperature of the water to suit both the plant and animal requirements. 
  5. Make sure the water has plenty of aeration. Fish, bacteria, and plants roots all require plenty of oxygen to maintain a healthy system. 
  6. Provide plenty of fish food. Fish that thrive in their environment will help the plants do the same. Fish that are fed well and consistently will go a long way to ensuring a healthy and bountiful organic crop production environment. 

To see a what a large, commercial farm looks like, check out this video.

Tour an AQUAPONICS FARM in Texas 🐟 + 🌿= 🤠 Sustainable Harvesters

What Is Aquaponics –  Final Thoughts

There are many definitions of aquaponics out there. In the end, it’s all about the collaboration between aquaculture and hydroponics. This method isn’t the easiest of ways to grow plants initially, but as your knowledge of aquaponics expands, it becomes one of the best sustainable methods to grow plants, while being easier to maintain. 

FAQs

1. Is Aquaponics Easy?

Aquaponics will take some time in the initial startup phase, but once the system is up and running, it’s easier to maintain. In fact, when compared to running a simple fish aquarium, an aquaponic system requires less maintenance to keep the water and tank clean. The plants act as a natural filter to keep a higher quality of water. 

2. Does Aquaponics Need Sunlight?

All plants need light to grow, however with full spectrum LED lights, it is perfectly possible to grow your plants using proper grow lights that mimic the sun’s light. 

3. Is Aquaponics Better Than Hydroponics?

It depends on what way you look at his question. On one hand, hydroponic systems are easier to control the desired nutrient levels and are certainly easier to get started. In the long run, aquaponic systems can provide more benefits. Aquaponics systems are self-sustaining and better for the environment. They produce more natural, organic crops and can be a lot of fun too with fish and plants.

4. How Much Does an Aquaponics System Cost?

There is a variety of systems that can be bought and built, so it’s difficult to place a average price on a system. For instance, this Back to the Roots Aquaponic Starter System comes in at under a $100 and is ideal for growing herbs. Larger systems like this AquaSprouts Garden are slightly more expensive, but still priced at well under $200. These are starter system kits that are ideal for beginners and kids. For more complex and larger systems, the sky is the limit when it comes to pricing. But remember, it’s possible to start small and build your system as your skills and knowledge develop. 

5. Can Aquaponics Be Organic?

By its very nature, the vegetables and herbs that you grow using an aquaponic system is organic. No pesticides or herbicides are used due to having fresh fish as part of the system. And because you have natural nutrients from fish waste, there’s no need for artificial nutrients or chemical fertilizers to promote plant growth. 

6. How Many Plants Per Fish With Aquaponics?

The ratio of plants and fish for aquaponics is dependent on a few variables including, the size of the fish, and the space available for both fish and plants. But as a general rule of thumb, consider starting with a ratio of 1 fish per 2 plants. It is worth researching this in greater depth once you have selected your system, and know which type of fish and plants you to intend to keep and grow. 

7. When Was Aquaponics Invented?

Forms of aquaponics can be traced back to the Aztec Indians, who were known to have raised plants on rafts over a millennium ago. Aquaponic and hydroponic systems, as we currently think of them, are a relatively recent form of agriculture that originated in the past 50 years.