Aquaponics is a blend of food production that has been around for decades but only recently has come into the limelight as an ideal way to produce protein, fruits, and vegetables in the same small space. Aquaculture is the raising of edible fish and hydroponics is the method of growing fruits, vegetables and herbs without soil. When the two are combined, it’s called aquaponics and when you do it yourself, it’s called DIY aquaponics.
The edible fish are grown in a tank of water and the fresh produce are grown separately from them, allowing for double the amount of food production in the same space. Aquaponics rely on a symbiotic relationship between the fish and plants for sustainability as well as producing a constant food source to support a sustainable lifestyle.
Before investing a considerable amount of money in ready-made equipment or systems to start raising edible fish and produce, consider a small DIY aquaponic system that you can build from recycled material. Re-use and re-purpose items you may already have on hand to promote sustainable living and to reduce the start-up cost of an aquaponic growing system.
Indoor or Outdoor
Before building an aquaponic system, decide where it will be located.
- Indoor locations will need to be away from the main living area, preferably in a room used only for aquaponics.
- Outdoor locations will need to be sheltered to protect fish and plants from the elements.
- A greenhouse is an ideal outdoor location.
- Indoor or outdoor locations will need easy access to water and electrical source.
Fish Tank
Any large water-tight vessel can be recycled into a fish tank.
- 55 gallon food grade barrel or a 225 food grade plastic bin are often used in DIY aquaponic systems.
- An old fish aquarium is ideal for a small, indoor set-up.
- Above ground plastic swimming pools also make good fish tanks as you advance in number of fish and plants.
- One fish per 10 gallons of water is a good starting point.
- Any existing live aquarium with no prior complex filtration system can be modified to accommodate aquaponics.
- The goal is to have one pound of fish per gallon of water in the tank, but this may vary with the species of fish as well.
Growing Bed
Plants grown in an aquaponic garden don’t need soil for their roots, but they still need some type of container for a growing bed.
- PVC pipe is often used in aquaponic and hydroponic grow systems.
- Large PVC pipes (4“in diameter) have small holes drilled in the bottom for water absorption and drainage with large holes drilled in the top to place plants.
- Large top holes are drilled at varying intervals, depending on the type of plants being grown. Small herb plants can be grown closer together than larger tomato plants.
- A wood or plastic box lined with pond liner can also be used for growing plants without soil.
- Perlite, gravel or coconut coir is used in grow boxes to keep plants stable.
Pumps and Hardware
A pump, along with tubing, will be needed to keep the water circulating. Electricity from solar panels will enable you to produce food off-grid year around with an aquaponic growing system. The water pump allows the aquaponic garden system to be a self-sustainable food source producer.
The pump floods the growing beds or PVC pipes with water to submerge the plant roots for a designated period of time each hour. The plants uptake the fertile water during this time and when the pump stops running, water recedes back into the fish tank to allow plant roots time to slightly dry out before the next watering.
- A timer will be needed for the pump because it does not need to run continuously. Start out with the pump set to run 15 minutes every hour. Adjust the time and frequency from there. The pump needs to run enough to keep the fish waste moving to the plant roots, but not so much that the plant roots are constantly in water. Experimentation is the only way to discover the right pump running time for an aquaponics system.
- An aerator will also be needed to keep the water oxygenated for the fish. The aerator must run 24/7 to provide a steady supply of oxygen.
- Grow lights will be needed for an indoor system. LED overhead lighting is popular due to their low energy usage, low cost, and no heat output.
Putting It Together
- Spring is the ideal time to get started so you enjoy a harvest of fresh fish and vegetables by the end of summer.
- Start plants from seeds in the late winter so they will be ready to plant one week after the system is built.
- Place fish in the completed tank first, then install and plant the PCV pipes or growing beds.
- Allow water to circulate with fish in it for one week before placing plants in the water. This will ensure the water has enough nutrients from fish waste to support plant life.
Plant Nutrition
The growing plants provide clean water for the fish and the fish provide food for the plants. The plants filter out all the fish waste and uptake the waste products as fertilize. The plants do such a good job filtering out the fish waste that there is no need to add clean water except to replenish water lost through evaporation.
The Fish
Tilapia are the most common type of fish used in any type of aquaculture. Tilapia reach maturity in six months and are hardy in most water conditions. The one thing to remember about raising tilapia as a food fish is that they are a tropical species and need warm water to thrive. Keep the water in the DIY aquaponic system between 70-80 degrees for healthy, thriving tilapia. Tilapia produce a lot of waste, which feeds the plants.
- Catfish are a hardy fish choice for colder climates or when keeping the water warm enough for tilapia is not possible. Catfish can be grown all year round.
- Another good fish choice is yellow perch. They are hardy fish and will thrive in cooler water.
- Fish are fed three times per day, as much food as they can consume in 20 minutes.
- Automatic feeders can be installed to streamline the process.
The Plants
Any plant that is harvested by the leaf is ideal for growing in an aquaponics system. These leafy greens rarely, if ever, will require extra nutrients to be added to the water.
- Kale
- Lettuce
- Basil
- Spinach
- Dill
- Arugula
Fruits like strawberries, blueberries and raspberries can also easily be grown without soil, but will require additional nutrients to be added to the water.
Tomatoes, squash, peppers and cucumbers are some of the popular vegetables to be grown aquaponically, but will require supplemental fertilizer to be added to the water during the growing season. When nutrients are added to the water according to manufacturer’s directions, the fish in the tank will not be harmed.
Adding On
Start out with a small DIY aquaponic growing system and add onto it as you learn and fine-tune the process. It’s possible to grow enough produce and fish to sustain a family with a DIY growing system. And it can all start with recycled material and a little elbow grease.
