Greetings from tropical paradise, Costa 
Rica. I’m here building the first stages of a Working Farm and 
School for Sustainable Aquaculture. For those unfamiliar with the term, Aquaculture is a farming method where fish farming is used in conjunction with hydroponic growing techniques in a “closed-loop”. In this first of an ongoing series, exclusively for The Garden Enthusiast - Backyard Nature Station, I'll touch on the basics of the techniques and provide some insight on our experiences growing and operating in paradise.

Aquaculture is perhaps one of the most efficient methods of food production ever devised, the yields of both fish and plant being higher than that if they were grown separately. In this symbiotic relationship the waste stream from the fish is converted into readily available nutrients by micro-organisms in a biofilter, then filtered through the root systems of the plants. This filtered and highly-oxygenated water is then returned to the fish. The system uses less than ten-percent of the water used in typical farming, needs no external fertilization, and is easily scaled from a small herb garden with a few goldfish to a large farm with thousands of tilapia, trout or other edible fish.

Our project aims to provide proof-of-concept to techniques that will easily transfer to your backyard, be self-sustaining, and, most importantly, provide food security for you and your family. Construction of Phase One of our project is underway with the 
building of a thirty-foot diameter geodesic dome greenhouse, fish ponds, and intrinsic systems including algae production, vermiculture (worm farm),  and a water purification system. All this is being contained in a seventy-foot square space, mimicking the area available in a typical backyard.

In conjunction with Phase-1 of construction, we have begun propagating plants to populate the greenhouse. We chose Botanical Interests seeds, which are GMO-free, and are having great success with them. Botanical Interests 
has signed the Safe Seed Pledge, as well as selling only untreated seeds, both important considerations in our decision to use their products. 

As far as grow medium, we are using Coconut Coir, the fibrous material that makes up the inner shell of coconuts. This highly renewable product was formerly just a waste by-product of coconut production, but has proven to be an excellent choice both as a soil amendment for legacy gardening as well as an excellent medium for hydroponics. It has good water retention properties while the fibers trap tiny air bubbles providing important root oxygenation. Finally, it is PH neutral, so it doesn’t have an impact on nutrient solution PH and can be used with any type of plant.

As an interim means of fertilization, we are using Alaska Fish Emulsion, a 5-1-1 formulation, for propagation and vegetation stages and Fox Farms Big Bloom, a .01-.3-.7 formulation, for flowering and fruiting stages. Both products are made from organic ingredients and can be applied without worry of “burning” the plants. Once the fish ponds are stocked, these products will not be necessary, although we are so happy with the results achieved that we highly recommend them and plan to continue to use them in other areas of the farm.

While Costa Rica is a gardener’s paradise, it is also the ideal environment for insects and fungus. We use two organic products to help battle these obstacles to success: Safer Insect Killing Soap and Evergreen Organic Fungicide-Bactericide. Another insect that is prolific here is the mosquito. While not a threat to the plants, they are a threat and a nuisance to people. We've tried a number of products, including the Off family of products, however our favorite (and the most effective/longest lasting) is Organic Insect Repellent Spray Oil. It’s made from natural oils, has a pleasant smell, and -most importantly - it works!

In next month’s update, we’ll begin talking about the individual systems that are being integrated into our project, provide insight on building a geodesic dome greenhouse, and discuss choosing the variety of fish to populate your aquaponics system. If you have questions about this article,  or our project, please feel free to contact me at [email protected]