The growing of plants without soil is called Hydroponics. It is widely used to grow lush, healthy indoor plants and good quality vegetables, fruits and herbs. Plants absorb nutrients as simple ions in water. The nutrients in the soil dissolve in water and the plant roots absorb them.
When the plants get adequate nutrients, the soil is no longer required for the plant to thrive. With the use of proper nutrients and the right artificial light source, an indoor gardener can achieve amazing results. A complete controlled environmental agriculture system should have controlled light, temperature, water, CO2, oxygen, pH and nutrients.
Hydroponics is simple and efficient. On alternate days a pH check is done and the water level is topped up. The nutrient is changed every 7 – 12 days. To turn the light and garden on and off automatically, a timer is often used.
Amongst the different forms of Hydroponics, deep water is the purest form since the roots are directly exposed to the nutrient solution. “Deep Water” systems use a small air pump to keep the solution well oxygenated.
Another method of Hydroponics is the Ebb & Flow or Flooding & Draining systems. The root system and growing mediums like Rockwool are soaked at specific intervals. The Ebb & Flow method makes it easier to cultivate plants in minimal space.
In Deep Water Culture (DWC), the roots are allowed to drop down into an aerated nutrient solution. This solution is aerated with the help of standard aquarium pumps and sir stones. The solution must be topped up from time to time. Drip feeding is similar to Ebb & Flow, except that the pump delivers a continuous tickle of nutrients and water.
The emitters run 5 to 10 minutes every hour.
Another method of Hydroponics is Wick feeding, where the plant draws water with the help of a wick which runs from the base of the plant container to a bottle of nutrient feed solution. Through capillary action, the solution travels up to the plant through the wick. In Raft cultivation, plants are inserted inside sheets of expanded polystyrene with the roots hanging down through the holes.
The sheet is then floated in a shallow tank of nutrient solution. In Nutrient film technique (NFT), the plants grow through light-proof plastic films placed over shallow, gently sloping channels. The roots grow into dense mats with a thin film of nutrients passing over them.
Aeroponics is a class of Hydroponics where the roots of a plant are suspended in a midst or fog of nutrient rich solution.
Different media are used for Hydroponics. Expanded clay, Rockwool, Coco coir, Perlite, Vermiculite and Oasis root cubes are some of them. Due to constant problems of chemicals and other contaminants in the food supply, people are looking for a safer alternative. Hydroponics fits the requirement appropriately.