Types of Aquaponics
Deep water culture (DWC)
Deep water culture (DWC) or raft based growing uses a foam raft that is floating in a channel filled with fish effluent water that has been filtered to remove solid wastes. Plants are placed in holes in the raft and the roots dangle freely in the water. This method is most appropriate for growing salad greens and other fast growing, relatively low-nutrient plants. It is also most commonly used in larger commercial-scale systems. Aquaponics uses highly nutritious fish effluent that contains all the required nutrients for optimum plant growth. Instead of discharging water, aquaponics uses the plants, naturally occurring bacteria, and the media in which they grow in to clean and purify the water, after which it is returned to the fish tank. This water can be reused indefinitely and will only need to be topped-off when it is lost through transpiration from the plants and evaporation.
Media growing involves growing plants in inert planting media such as expanded clay pellets or shale. The media provides both the biological filtration (conversion of ammonia to nitrates) and mechanical filtration (removal of solid wastes) in the same system. Media based systems are great for home and hobby scale systems so you can grow a wide variety of crops. In particular, large fruiting plants do really well in addition to leafy greens, herbs and other varieties.
Nutrient Film Technique (NFT)
NFT systems work by flowing nutrient-rich water through a narrow trough, such as a PVC pipe. Plants are placed in holes drilled in this pipe, and the roots dangle freely in this stream of water. This method of growing works very well for plants that need little support, such as strawberries (pictured) and other herbs. NFT is also a great way to utilize unused space because they can be hung from ceilings above other growing areas.
One of the greatest aspects of aquaponics is its ability to grow an incredible amount of food in a very small area. In vertical aquaponics plants are stacked on top of each other in tower systems such as the Aqua Vertica. Water flows in through the top of the tower, and flows through a wicking material that the plants roots absorb water and nutrients from. The water then falls into a trough or directly into the fish tank. This form of agriculture makes the most of each square foot of space, and works very well with leafy greens, strawberries, and other crops that do not require support to grow.
Tips on an Aquaponics setup:
- You can make your own aquaponics system and here is a simple and complete guide you can use to make one. Start small see if it’s good for you then feel free to go bigger.
- Have set a different power source as a backup. It’s vital to keep the water flowing and the oxygen pumps on.
- Make sure you feed the fish enough and let them thrive. Depletion of fish stock makes this type of cultivation impossible
- Keep food input constant for the fish and that will result in regular fish waste you can use to feed your plants.
- Ensure your plants and fish with good aeration. Not only the plants need their roots to be oxygenated, but also, the fish and the bacteria need the water to be oxygenated. As the fish grow bigger, their oxygen needs increases and you might need to adjust accordingly.
- When you decide what plants you want to grow, pick the ones that have similar water condition needs as the fish, and you will have greater success.
- Remove some excess fish waste when necessary. Too much can harm the health of the fish.
- Keep an eye on the level of pH because as shown above, it is crucial for the garden.
- Fish tanks should be made of glass or food grade plastic.
- Avoid using any pesticide other than organic, or any other substances that can and will harm the fish or the good bacteria (vinegar, citric and/or hydrochloric acid).