Is Aquaponics for You? Realities and Potentials for Arkansas
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Aquaculture/Fisheries FSA9618 Is Aquaponics for You? Realities and Potentials for Arkansas • Easy harvesting (no need to Matt Recsetar Soilless Gardening bend over) Extension Aquaculture Aquaponics is becoming a popular Specialist • Easier pest control due to way to grow your own plants and fish elevated growbeds in a chemically safe and relatively • Higher yields Anita Kelly sustainable manner. It combines Extension Fish Health aquaculture systems used for growing • Stable crop yields in small Specialist fish with hydroponic cultivation systems of plants. • Less climate restrictions For all practical purposes, • Proven technology with numerous hydroponics is a type of soilless commercially viable hydroponic gardening that involves growing systems plants in water supplemented with nutrients. This enables plants to freely absorb required nutrient ions Disadvantages of Hydroponics from the water contained within a • Expensive nutrient solutions given system. Nutrient concentrations • Nutrients more difficult to keep in the water must be measured and in balance maintained at specific levels based on the types of plants being grown. • Salt accumulation Although water must be added to the • Installation costs system to account for evaporation and transpiration, it is estimated that • Technical skill required to cope hydroponic gardening utilizes one with soilless culture systems tenth the amount of water used in traditional terrestrial gardening. Aquaponics provides the same There are numerous advantages and benefits for plant production as disadvantages of hydroponics over hydroponics but comes with the traditional soilbased gardening. increased complexity of managing both fish and plants integrated into one system as well as the bacteria Advantages of Hydroponics that converts fish wastes into fertil • Lower water requirement izer (Figure 1). However, instead of having to constantly add and measure • Controlled system plant nutrients as with hydroponics, • Avoid most soilborne diseases plant nutrients come predominantly University of Arkansas at Pine Bluff, United States Department of Agriculture, and County Governments Cooperating dechlorinate the water before stocking fish and any time water is added to the system. Chlorine used in municipal water will kill your fish. Figure 1 • What can be done if the Figure 1 fish get sick? It is impera tive that the disease be diagnosed and treated. Unfortunately, most treat ments for fish diseases are not safe for plants. You will need to have a separate treatment tank or a method to make sure the plants are not exposed to the treat ment required by the fish. from the fish production tank. In appropriately designed aquaponic systems, fish provide adequate nutrients for the plants. Three Types of Aquaponic Systems There are three main types of aquaponic systems with different advantages and disadvantages Things to Consider (Table 1). Some types are more suitable for backyard When Caring for Fish or smallscale systems while others work best for Caring for fish in an aquaponic system adds large commercial hydroponic systems. considerable complexity to an indoor gardening system. The following are key questions that should Floating Raft (Deep Water Culture) Systems be considered carefully before investing in an aquaponic system: The floating raft system (Figure 2) involves growing plants supported by polystyrene (or similar) • Do you have the time to care for fish? Fish need rafts that float on top of a relatively deep (1224 inch) to be fed every day, so if you plan on going out of water trough. The plants are supported by the rafts town for a week, you will need someone to feed and maintain fish while you are gone. • What will you do if you lose power? Fish require good water quality which includes adequate oxygen levels and minimal nitrogen levels. If you are not around and the power goes out, you risk losing fish due to lack of oxygen from aeration and filtration. Even if fish do not die during a power outage, they may become more stressed, which can lead to disease outbreaks. • What is your water source? Use only well water, uncontaminated rain water or treated municipal water. If municipal water is used, you will need to Figure 2. Floating Raft System while their roots are directly submerged in the commercial systems for production of herbs and leafy nutrientrich water below. Floating raft systems greens, although individuals have utilized this design are generally used in commercial aquaponics for to maximize space at home. production of herbs and leafy greens. Flood and Drain Systems NFT Systems Flood and drain systems (Figure 4) involve grow The nutrient film technique (NFT) (Figure 3) ing plants in a mediafilled growbed that regularly involves a trickling or low flow of nutrientrich water fills and drains with nutrientrich water. The ebb and down an inclined pipe or gutter. The plant roots hang flow of water in the growbed allows for root aeration down and draw up nutrients as needed from the film and helps prevent anaerobic conditions that might of water while still allowing for a portion of the roots otherwise occur. The flood and drain system is used to be aerated. NFT systems are commonly used in frequently for homebased aquaponics. Figure 3. NFT System Figure 4. Flood and Drain System Table 1. Choosing the Right System System Type Pros Cons – Easy plant rotation – Limited to herbs and leafy greens – Great for lettuce and herbs – More aeration needed Floating Raft – Can withstand power outages – Need separate biofilter (DeepWater Culture) – Most resistant to temperature and pH fluctuations – Great for herbs and leafy greens – Plants will die quickly if pump clogs – Can utilize limited space or stops functioning NFT System – Allows for root aeration – Need separate biofilter and – Fish and plants can be decoupled solids removal – Water temperature fluctuations – Can grow almost anything – Bell siphon required (can be tricky) – Growing media acts as biofilter and – Media can be expensive Flood and Drain mechanical filter – Pump more likely to clog (in fish tank) (Ebb and Flow) – Allows for most intense plant spacing – Simple design While having an additional crop with fish can Growing Strategies seem like a good idea, this isn’t always enough to The climate in Arkansas ranges from hot and offset the large cost associated with adding the aqua humid in the summer to cold and snowy in the culture component. Tanks, plumbing and fish feed are winter. The typical growing season for most fish and all large costs, plus there is added risk created by the plants ranges from April to October but will do best fish. The fish themselves will require additional care, with increased sunlight and temperatures above so hydroponics may be a better alternative for indi 65°F. Before investing in aquaponics, you will need viduals who do not have time every day to feed and to decide on a growing strategy. care for their fish. • Grow indoors – Can grow crops year round, will need UV grow lights. Important to consider water Harvesting spillage if you are choosing this option. Fish and plants need to be harvested from your system to maintain balance. Some plants can over • Grow outdoors – Generally you can grow crops grow your system and so need to be continuously from May to September, so will have to either pruned and harvested. Some leafy greens grow bitter shut down in the winter or bring the system if left in your system too long, while fruits can go bad indoors. This is the most common strategy for if left to overripen. Techniques and strategies from smallscale aquaponics and likely the lowest traditional gardening should be applied where neces cost as you do not need to purchase grow lights sary. Edible fish should be harvested once they reach or a greenhouse if you plan on shutting down in market size and replaced as needed. the winter. • Grow in a greenhouse – Without heating the Food Safety greenhouse, the growing season is from March Food safety is another important concern for until December. With some heat, plants and fish aquaponic gardens. Foodborne illnesses are a major may be able to survive through the winter but will not grow as quickly without additional light. issue, so it is important to take steps to reduce possi Without additional heat or light, how much ble contamination of your produce. Proper hygiene slower they grow depends on the plants and fish should be practiced, and hands should be washed species in the system as well. prior to touching any plants. Any time produce is harvested, latex, rubber or nitrile gloves should be worn, and every effort should be made to avoid con Backyard Aquaponics tact between the produce and the growing media. Size of your system is another important Storage facilities and containers should be kept clean consideration when setting up an aquaponic system. and surfaces that will come in contact with produce The larger the system, the more time and effort it should be sterile. will require to maintain. Smallscale or backyard aquaponics is a great Other Considerations way to produce your own food and also serves as a • Do you have adequate space available for use, useful learning tool for schools and communities. and at what cost? Investments can range from $100 if you are using a 10gallon aquarium to grow herbs to well over • Do you have a well? Well water generally has $50,000 if you buy a greenhouse, depending on the higher alkalinity than municipal water which size of the system and the materials used to build it. helps stabilize the pH of your system. This can Typically you can save over 50 percent of the cost if be a potential benefit to you and your plants. you build it yourself. It is a good idea to make sure the fish you plan to Choosing Fish grow is on the Approved Aquaculture Species List or You will need to obtain an Arkansas fish you will need to apply for a restricted species posses farmer permit from the Arkansas Game and Fish sion permit or unlisted aquaculture species permit Commission (AGFC) if you plan to sell your fish.