Aquaponics is the combination of raising fish (aquaculture) and the soil-less growing of plants (hydroponics) together in one integrated system.
The waste from the fish feeds the plants, and the plants naturally filter the water for the fish.
There is a third very important participant and that is microbes (bacteria). These convert ammonia from the fish waste first into nitrites, and then into nitrates.
Nitrates are the form of nitrogen that plants can uptake and use to grow. Solid fish waste is turned into vermicompost that also acts as food for the plants.
This may sound complicated but believe me, it’s not that difficult and I will try to make this as easy to follow as I can.
Why Not Just Grow Plants the Usual Way?
Traditional soil-based gardening has its problems that just aren’t present with aquaponics such as:
- The use of pesticides and artificial nutrients
- Weeds, pests, and soil-borne insects
- The amount of water that is required
- The heavy digging, the bending, the back strain
- The knowledge required to know when to water, when and how to fertilize, and what the composition of the soil is
- Location – traditional farms are often located thousands of miles from where the food is consumed
While the above problems can be solved with hydroponics, hydroponics also has its own problems such as:
- Traditional hydroponic systems rely on the careful application of expensive, man-made nutrients made from mixing together a concoction of chemicals, salts, and trace elements. In aquaponics, you merely feed your fish inexpensive fish feed, food scraps, and food that you grow yourself.
- The strength of this hydroponic mixture needs to be carefully monitored, along with pH and total dissolved solids (TDS). In aquaponics you carefully monitor your system during the first month, but once your system is established you only need to check pH and ammonia levels weekly or if your plants or fish seem stressed.
- Water in hydroponic systems needs to be discharged periodically, as the salts and chemicals build up in the water, becoming toxic to the plants. In aquaponics, you do not need to replace your water; you only top it off as it evaporates.
- Hydroponic systems are prone to a disease called “pythium” or root rot. This disease is virtually non-existent in aquaponics.
The Benefits of Aquaponics
- Waist-high aquaponic gardening eliminates weeds, back strain, and small animal access to your garden.
- There is no toxic run-off from either hydroponics or aquaculture.
- Aquaponics uses only 1/10th of the water of soil-based gardening and even less water than hydroponics or recirculating aquaculture.
- No harmful petrochemicals, pesticides, or herbicides can be used. It’s a natural ecosystem!
- Gardening chores are cut down dramatically or eliminated. The aquaponics grower is able to focus on the enjoyable tasks of feeding the fish and tending to and harvesting the plants.
- Aquaponic systems can be put anywhere, in the garden, or even in the home.
- They are scalable and can fit almost any budget.
- And the best part – You get to harvest both plants and fish from your garden. Truly raising your entire meal in your backyard.
In short, aquaponics is an absolutely incredible system for producing food for people without creating any waste products or pollution.
During this guide, I want to give our readers an overview of aquaponics and the information you need to get started. If this post is a success and our readers want more, I am more than willing to go even deeper into the subject through other posts.
To avoid becoming overwhelmed, I suggest that you just start small to get a better understanding of how it works, and then you can scale it up from there.
The Basic Components
No matter what size of the aquaponics system you choose to put together, the components below will always be included. There are many options to add on to these and customize the system, depending on your particular circumstances and goals.
For beginners to get a feel for how it all works, I suggest starting out with one fish for every 10 gallons of water.
Your tank can be anything from food-grade barrels to vinyl swimming pools depending on space but I suggest to starting out with either a 55-gallon barrel or a 225-gallon square bin.
The Grow Bed
You will need some form of water-resistant container to house the soil-less medium that your vegetables will be grown in. These can very easily, and cheaply, be made at home.
The simplest approach is to build shallow wooden boxes (6 to 10 inches deep), as you would for vegetable raised beds in the garden. These can then be lined with pond liner.
These beds are then filled with an inert growing medium, such as perlite or fine gravel. Coco coir is the fanciest growing medium available and is often used by professionals for its ability to retain air and moisture simultaneously.
You can plan to ferti-gate a growing area up to 10 times the surface area of your fish tank.
Pumps and Hardware
There is actually not as much hardware as you would expect in an aquaponics system. The plants filter the water of waste, allowing them to thrive without ever adding freshwater, while the nutrients in the wastewater are the perfect fertilizer for most herbs and vegetables.
Thus, a pump is needed to circulate the water between the two components and to make the self-sustaining system go round. You could opt for a solar-powered pump to make your aquaponics system almost entirely self-sufficient.
It is the pumps and the piping where people are likely to get confused as it can be a little tricky. The pump can either collect the water that drains from the grow beds and put it back in the tank (if the grow beds are below the tank), or it can be placed in the bottom of the tank and used to spread the water over the surface of the grow beds (if they are elevated above the level of the tank).
The beds themselves need a network of PVC pipes on the surface to distribute the water from the fish tank. Drill ¼-inch holes every 6 inches in the pipe and structure the beds with several parallel pipes, each about 12 inches apart. You can plant a seedling at each of the little holes in the PVC pipe.
There is one more absolutely critical piece of hardware to make an aquaponics system work: you need an aerator to provide sufficient oxygen for the fish.
The most common species of fish used in small scale aquaponics is Tilapia. They are a tropical species though and will need the water temperature to stay between 70 and 90 degrees to stay healthy and grow quickly. They grow fast and reach a harvestable size of one pound in 6 to 8 months.
Catfish are also very amenable to high-density recirculating aquaculture systems and have no problem overwintering in all but the coldest climates, though they only put on growth when the water is warm.
The third most common species is Yellow Perch as these have the advantage of being able to put on growth in cooler waters.
Some food plants are better suited to aquaponics systems than others. Basically, anything that is harvested as a leaf—lettuce, kale, arugula, spinach, basil, dill, etc.—responds very well to the nutrients found in fish water and can usually be grown without added nutritional supplements.
It is also possible to cultivate species grown for their fruit, such as blueberries, strawberries, raspberries, etc., as well as vegetables like tomatoes, cucumbers, and zucchini, although these typically require supplemental fertilizers.
Putting it All Together
You will need a flat, sunny space to set up your aquaponics system. It will be better to put together in the spring unless you are choosing to build it in a greenhouse.
As soon as the water reaches a steady 70 degrees, you can stock the fish. Stock the fingerlings first and start seedlings in flats of potting soil at the same time. This way, by the time the seedlings are big enough to transplant, the fish should be producing enough waste to support the growth in the grow beds.
Incidentally, the vegetables themselves have very little to do with cleaning the water for the fish—this actually occurs in the growing medium, so the water needs to circulate through the grow beds for the sake of the fish, whether there are plants growing in them or not.
The aerator will need to be run 24/7 in order to provide oxygen to the fish. The pump should be on a timer that turns it on for short periods of time, several times a day. This will take some experimentation on your part but the goal is to run it as much as possible to keep the water clean for the fish, but you’ll have to limit it to prevent the growing medium from remaining excessively wet.
The fish are typically fed as much food as they can consume in 20 minutes three times per day. There are automatic feeders and many other optional components that can streamline and automate the system, which can make the feeding process a lot easier. The key is to start small and simple and to not push the system too hard by overstocking the fish.
Overfeeding the fish is the easiest mistake to make and will quickly result in degraded water conditions. Once you have a simple system and an established routine that works for you, build on your success by expanding your system.
Check out the videos I have found below for some ideas.