Aquaponics refers to the growth of plants in water and fish farming. The water is nourished with the waste from farm fish and other aquatic creatures which supply the nutrient to the plants. The plants in turn purify the water in which they are grown. And because it is a kind of automatic recirculation, not much monitoring is required. The symbiotic arrangement is quite self-sustaining and requires little or no maintenance. Many persons have taken to aquaponics, both as a hobby as well as a commercial venture.
Based on one’s needs, aquaponic systems can be categorized into:-
1. Media based system - The simplest one is the Media based system. In this system, there is a gravel bed. This is the easiest to set up and can be done on a small or large scale depending on requirement and therefore, this is the favourite of most home gardeners. In this system, containers are filled with porous small rocks. Clay pebbles that are porous can also be used. The rocks and pebbles should be capable of absorbing water and air. The seedlings are then planted directly into these containers. The water containing the nutrients is circulated through these containers. The plants can access the nutrients contained in this water. The rocks and gravel act as a natural filter for solid particles and this does away with the need for any additional filtration equipment.
If it is necessary that the plants should be held firmly, such as for fruit bearing plants, then a wire mesh can be used to hold the gravel and rocks. Coir and peat moss can be added and the whole thing can be contained in mesh bag in which the plant is put. The whole mesh net can then be put into a container in which water is circulated. The circulation of water can also be done in two ways – either the water can be pumped from the fish tank directly to the plants and then back into the fish tanks or the water can be arranged to flow in an ebb and flow sequence which can be controlled.
2. NFT System or the Nutrient Film Technique - The NFT System or the Nutrient Film Technique is ideal for large scale hydroponics. In this system the netted plants are suspended from holes in PVC pipes. A system of gutters is built so that the roots of the plants can reach the nutrient rich water. This is suitable only for plants with small root systems. This is suitable only for large scale production because of the expense involved in setting up a system of PVC pipes and mechanical filtration equipment.
3. Deep Water Culture or the Raft System - A third system is the Deep Water Culture or the Raft System. This is suitable for both backyard aquaponics as well as for commercial production as this is relatively cheap to set up. A foam raft floats in the water and the plants are put in holes made in the water in such a manner that the roots are dipping into the water. This is also suited for plants with smaller root systems.
Aquaponic system maximizes crop yield while protecting the environment.