Aquaponic Gardening

A Step-By-Step Guide to Raising Vegetables and Fish Together

Sylvia Bernstein

• Publisher: New Society Publishers
• Year: 2011
• ISBN:
  9781550924893
• Topic: Ciencias biológicas
• Subtopic: Horticultura

Dive into home aquaponics with this definitive do-it-yourself guide

Aquaponics is a revolutionary system for growing plants by fertilizing them with the waste water from fish in a sustainable closed system. A combination of the best of aquaculture and hydroponics, aquaponic gardening is an amazingly productive way to grow organic vegetables, greens, herbs and fruits, while providing the added benefits of fresh fish as a safe, healthy source of protein. On a larger scale, it is a key solution to mitigating food insecurity, climate change, groundwater pollution and the impacts of overfishing on our oceans.

Aquaponic Gardening is the definitive do-it-yourself home manual, focused on giving you all the tools you need to create your own aquaponic system and enjoy healthy, safe, fresh and delicious food all year round. Starting with an overview of the theory, benefits and potential of aquaponics, the book goes on to explain:

• System location considerations and hardware components
• The living elements — fish, plants, bacteria, and worms
• Putting it all together — starting and maintaining a healthy system.

Aquaponics systems are completely organic. They are four to six times more productive and use 90 percent less water than conventional gardens. Other advantages include no weeds, fewer pests, and no watering, fertilizing, bending, digging, or heavy lifting – in fact, there really is no down side! Anyone interested in taking the next step towards self-sufficiency will be fascinated by this practical, accessible and well-illustrated guide.

Section 1

An introduction to aquaponics

“Here’s to the crazy ones. The misfits. The rebels. The troublemakers. The round pegs in the square holes. The ones who see things differently. They’re not fond of rules. And they have no respect for the status quo. You can quote them, disagree with them, glorify or vilify them. About the only thing you can’t do is ignore them. Because they change things. They push the human race forward. And while some may see them as the crazy ones, we see genius. Because the people who are crazy enough to think they can change the world, are the ones who do.”

— Apple Inc.

After breakfast Luna, my nine-year-old Tibetan terrier, runs to the door that leads to the back deck whenever I approach it. She knows that soon we need to go feed the fish. After several false alarms, the moment finally arrives when I open the door. She races down the stairs, banks around the corner and skids to a stop in front of the greenhouse. When I finally join her, I open the door and we are both momentarily overwhelmed by the sights, smells and sounds that greet us every morning.

The winter aquaponic garden in my greenhouse is alive in a way that the cold, still outside garden can’t possibly aspire to. The warm, moist air smells slightly like freshly turned earth after a spring rain. The sound of flowing water tells of life and energy. The vibrant green plants in various stages and sizes are bursting with promise and productivity. A ladybug flies by. But the best part is the fish. I glance down at Luna, who has pulled herself up on the rim of my 300-gallon stock tank with her front paws to peer at the community within. She never tires of watching them, forever hopeful that someday, if they get just close enough, and she is just fast enough, just maybe…

The author and her dog.

Image Credit: Benjamin Rasmussen

Welcome to aquaponic gardening. With this book I hope to take you on a journey through an entirely different way of gardening. You will learn how to grow plants in rocks using only fish waste as the fertilizer source and bacteria and worms as the bridge between barren toxicity and harmonious fertility. It sounds simple, and in many ways it is, but it can also have a profound effect on your ability to feed yourself and those around you.

With this technique you will learn how to grow edible fish to supplement your family’s diet with safe protein you raised yourself. You will learn to grow fruits, vegetables and greens using less than a tenth of the water and without the weeds of a traditional soil garden. And you will be able to grow food anywhere, without the restrictions of soil and sunlight.

Aquaponic gardening is a fascinating and enjoyable hobby, but fair warning — it can be very addictive. Yes, it is a healthy addiction, like yoga or salads, but an addiction nonetheless. For some, this means expanding from time to time to keep “the itch scratched.” I’ve seen systems start with a 30-gallon aquarium and one small bed, then become 300 gallons and four beds. Pretty soon the addicts are raising bass and trout in a newly converted backyard pool.

My personal experience has been a tale of expansion as well. I started with a 70-gallon pond liner from Home Depot. When that sprung a leak (I didn’t puncture it, I swear), I replaced it with a 120-gallon version — the fish were getting bigger and needed more room, right? Now I’m up to 120 tilapia and assorted goldfish in five tanks — four 60-gallon and one 300-gallon. Sad but true. Save yourself while you still can.

1

What is aquaponics?

So what is this crazy, addictive gardening technique? Here is one attempt at a definition:

Aquaponics is the cultivation of fish and plants together in a constructed, recirculating ecosystem utilizing natural bacterial cycles to convert fish waste to plant nutrients. This is an environmentally friendly, natural food-growing method that harnesses the best attributes of aquaculture and hydroponics without the need to discard any water or filtrate or add chemical fertilizers.

— Aquaponic Gardening Community, November 2010

The above was the result of a month-long online effort to define this thing called aquaponics. It is an excellent starting point for describing what it is that separates aquaponics from any other growing system available today. Let’s look under the hood at the individual components of this definition:

1. “cultivation” — This is a system of agriculture for growing the plants and fish we want to consume, rather than a description of a wild, uncultivated environment.

2. “fish and plants together” — These four words describe the heart of aquaponics. Without fish and plants being grown together, you don’t have aquaponics.

3. “ecosystem” — The dictionary defines an ecosystem as “a system formed by the interaction of a community of organisms with their environment.” Aquaponics is an ecosystem of plants, fish, bacteria and worms.

4. “constructed ecosystem” — This eliminates plants being grown on the shores of a lake or pond from the definition of aquaponics. While we are centering on a notion of an ecosystem, it must be an ecosystem that is constructed for the purpose of growing fish and plants together.

5. “recirculating ecosystem” — This constructed ecosystem must also retain its water by recirculating it rather than allowing it to drain off into the water table. This is why aquaponics uses so little water compared to the systems that spawned it.

6. “utilizing natural bacterial cycles to convert fish wastes to plant nutrients” — This speaks to the key mechanism that enables aquaponics to work. Without the nitrifying bacteria that convert the fish waste into plant food, the fish would soon die in their own waste, and the plants would starve for lack of nutrition.

In other words, aquaponics is a system where plants and fish are grown together symbiotically. The waste product from the fish provides the food for the plants, and the plants in turn filter the water that goes back to the fish.

Image Credit: The Aquaponic Source

This is an environmentally friendly, natural food-growing method that harnesses the best attributes of aquaculture and hydroponics without the need to discard any water or filtrate or add chemical fertilizer.

The second part of the definition focuses on the key benefits of aquaponics and introduces the notion that it is really the combination of two other sophisticated cultivation techniques: hydroponics and aquaculture. Both of these techniques require more intervention than an aquaponics system. Aquaculture has to ensure that the waste from the fish is removed before it builds to toxic levels, or the fish will die. Hydroponics requires a constant replenishment and manual balancing of the chemical nutrients, or the plants die. By combining the two systems, aquaponics transfers much of the responsibility for reaching equilibrium between the filtration of the fish waste and the nutrient needs of the plants to Mother Nature.

The second part of the definition also asserts that in combining these two techniques, the major problems of each are solved while the major benefits are retained. That is an incredible assertion. Before we go there and decide whether or not it is valid, we should take a moment to talk about hydroponics and aquaponics.

Hydroponics

Hydroponics is a method for cultivating plants without soil, using only water and chemical nutrients. The “ponics” in “aquaponics” comes from hydroponics. The term “hydroponics” literally means “water working”. Much of the greenhouse tomato, basil and lettuce production in North America today is done using hydroponic growing techniques, but you might have also heard of it because it is the favored growing method of marijuana producers.

Aquaponics is a hydroponic growing method in that it requires no soil. In both methods, the plants’ roots are constantly bathed in highly oxygenated, nutrient-rich water, and both see growth rates far above those found in soil-grown plants.

Aquaponics also borrows from many of the classic hydroponic system types. The flood and drain (also known as ebb and flow) style of growing on which this book focuses comes from the hydroponic world, as do NFT (nutrient film technique) and DWC (deep-water culture or raft) styles.

Pepper in hydroton®.

This is where the similarities end, however. Aquaponics is an improvement over hydroponics for the following reasons:

1. Expensive chemical nutrients are replaced by less expensive fish feed. Hydroponic nutrient solutions are expensive, and are gradually becoming more expensive as some ingredients are becoming over-mined and increasingly difficult to acquire. A gallon of hydroponic nutrient solution costs $30–60, and a few tomato plants will easily go through that during their productive lifetime. Meanwhile, a 50-pound (23-kg) bag of tilapia feed costs about the same amount, and at a 1.3 feed conversion ratio will give you 38 pounds (17 kg) of mature tilapia and simultaneously support about eight tomato plants.

2. You never dump out your nutrient solution. Water in hydroponic systems needs to be discharged periodically, as the salts and chemicals build up to levels that become toxic to the plants. This is both inconvenient and problematic, as the disposal location of this waste water needs to be carefully considered. In an aquaponic system, rather than having these problems with chemical imbalance, you achieve a natural nitrogen balance that is the hallmark of an established ecosystem. The water in your system is a critical component that you nurture as part of that balance. In aquaponics, you never replace your water; you only top it up as it evaporates and transpires (evaporates from the leaves of the plants). This saves both water and time.

Recirculating aquaculture tanks.

3. Maintaining an aquaponics system is significantly easier. I’ve spent years running both system types, and I can assure you that once cycling (starting the system by building the bacteria base or biofilter) has taken place, an aquaponic system is significantly easier to maintain than a hydroponic system. Hydroponic gardeners are instructed to check the EC (electrical conductivity) with a special meter daily, or at least once every few days. In aquaponics testing, this frequently just isn’t necessary. Because an aquaponic system is a natural ecosystem, it will tend to move into a balanced steady state. You will need to check pH and ammonia once a week and the only other check — for the nitrate level — can be run monthly.

4. Aquaponics is more productive. A university study by the Crop Diversification Centre in Alberta, Canada (Savidov, 2005), has shown that after six months, when the aquaponic biofilter is fully established, a grower will see faster and better growing results with aquaponics than with hydroponics.

5. Aquaponics is completely organic. Hydroponics is growing in a sterile, man-made environment. Traditional hydroponic systems rely on the careful application of expensive nutrients made from mixing together a concoction of chemicals, salts and trace elements. In aquaponics, you create a natural ecosystem where you rely on bacteria and composting red worms to convert the ammonia and solid waste from the fish into a complete plant food. It is a necessarily organic process. If pesticides are applied to the plants, the fish will suffer. If growth hormones or antibiotics are given to the fish, the plants will suffer. Aquaponics relies on nature and is rewarded through better growth, less maintenance and lower disease rates.

Aquaculture

The “aqua” in “aquaponics” means “water” and refers to the aquaculture side of the aquaponics equation. The dictionary defines aquaculture as “the cultivation of aquatic animals and plants, especially fish, shellfish and seaweed, in natural or controlled marine or fresh water environments.” Clearly aquaponics has a foundation in aquaculture in that the nutrients for the plants come from fish. Many of the early pioneers in aquaponics come from aquaculture academia, such as Dr. James Rakocy, who wer...