Aquaponic farming is an ancient farming method that uses fresh water fish to grow plants. In our aquaponic system here at The Farm, LLC we have a closed loop system that is comprised of fifty-two grow beds, each bed is four feet by five feet equaling twenty square feet of grow space per bed. There are thirteen rows in our greenhouse with each row having four grow beds. This gives us a total space of 1,040 square feet to grow plants in. Our grow beds are all flood and drain and filled with expanded Oklahoma red clay. There are also four 1,000-gallon fish tanks and a 1,500-gallon sump tank.
All four fish tanks and the grow beds drain into the sump tank. The water is pumped out of the sump tank and forced through our filter which is filled with a polymer bead that is food grade. The polymer beads are specifically made so beneficial bacteria can grow on them. As the water moves through the filter all the fish emulsion is collected so that only clean water comes out. Most of the water is diverted back to the fish tanks while the rest is sent to the fish tanks. There is no need for air stones for this system as air is constantly added throughout the process, air is being added as the water drains from the grow beds, more air is added as the water from both the grow beds and fish tanks are dumped into the sump tank, and then air is added to the water as the water enters the fish tank. The only electricity that is required to run the entire system is what that water pump uses. The rest of the system is passive.
The grow media which is comprised of the expanded Oklahoma red clay is between half and inch to three quarters of an inch in diameter. This size of expanded clay gives the roots plenty of growing room while maximizing the surface area that water, air and beneficial bacteria grow on. Expanded clay is porous allowing water and air to be trapped inside so the roods never go without either. Even if a grow bed is drained of all water the expanded clay will hold enough moisture to support plants weeks if not months. The benefit of a flood and drain system is that there is constantly a new supply of oxygen and water entering the grow bed. Water can become stagnate if not moving or circulating in the correct volume.
Fish food is the primary nutrient impute for this system. Each week I spray the plants with organic potassium and add iron to the water once a month. Fish require very little iron, but plants require a large amount, so iron must be added, or the plants become iron deficient.
There are other types of aquaponic systems that can be used. One of the most popular is Deep Water Culture (DWC). DWC has rafts that float on top of the water, the rafts have holes cut into them that contain net pots. The plants are placed in the net pots, so the plants roots are always in the water. Air stones must be placed in the water, so the roots can have adequate oxygen to them. This system is generally used for lettuce production.
We are using aquaponic farming as our key farming method. This allows us to start all our own bedding plants from seed, a year-round production of lettuces, and herbs. The fish emulsion rich water that comes out when we backwash our filter is used to water the crops grown in soil inside of the hoop houses and the garden areas that are outside. All seeds are GMO free and organic methods are used throughout the entire gardening operation. One of the benefits to aquaponic systems is that they can be made to be any height or width. There’s no weeding to be done, watering is not a concern and there is no soil that can splash upon the plants transmitting different diseases. You also can control pests a little easier.