Lekhika Borgohain

Do you know that there are some technologies in which plants do not need soil to grow?

Hydroponics is the technique in which plants can grow without soil. Nowadays everyone is moving towards cities. People want a better life, they want to have everything close by which is available. Cultivable areas are shrinking day by day due to the rapid growth of population. The solution for the future will be urban agricultural technology like hydroponics in which we can grow more food in less areas/soil. Many people think of hydroponics as growing plants in water. But hydroponic production actually is defined as growing plants without soil. This is a system where greens are grown organically without soil, with nutrients and with 90% less water. Hydroponic flowers, herbs and vegetables are planted in inert growing media and supplies with nutrient-rich solutions, oxygen and water.

To maintain a flourishing hydroponic system, few components are required like proper growing media, net pots, pipes, air stones, pump, etc. Hydroponics can be done by using all recyclable organic substrate like rice husk, volcanic rocks/aqua clay pebbles, coco coir, saw dust, coffee husk, wood dust, peat moss, etc., as the growing media. Coco coir is mostly used in hydroponic technology as the water retention capacity and air porosity is very high in coco coir. The coffee husk is not used as much, it is mostly used to oxygenate other media. Some inorganic media like perlite, pumice rock, vermiculite, sand, volcanic rock, clay pebbles, rockwool, etc., are there. Among all these inorganic media, vermiculite, perlite, rockwool and clay pebbles are mostly used with organic media coco coir.

Using hydroponics technology, everyone can produce food with high nutritional value. Since there is no need for soil in the hydroponic system, every inch of open space with sunlight and clean water can be used to grow vegetables and herbs in cities. Areas like rooftops, balconies, open space lying unused, empty space within buildings, etc., can be used for growing food.

Modern hydroponic systems are very sophisticated. There are systems that will monitor the level of nutrients, pH and temperature of the water and even the amount of light the plants are receiving.

There are three main types of hydroponic systems: nutrient film technique, ebb and flow system, wick system, drip system, aquaponics and aeroponics. A nutrient film hydroponic technique involves plants being grown in a grow tray that is slightly angled and positioned above a reservoir filled with the water-nutrient mix. This allows a thin stream of water to flow across plant roots and allows the plants to have sufficient water, nutrients, aeration and then drained back into the reservoir. This is the most common hydroponic system used. The ebb and flow system allows plants to be flooded with the nutrient-rich water and after the plant roots uptake nutrients, water is actively drained back into a reservoir to be reused. Wick hydroponic system is the simplest of all, as nutrients are passively given to the plant from a wick or piece of string running up to the plant from the water reservoir. In this system, plants are grown in an inert growing medium as mentioned above. Aquaponics refers to a food production system that couples aquaculture (raising fish, snails, prawns in tanks) with hydroponics in a symbiotic environment whereby the nutrient rich aquaculture water is fed to hydroponic grown plant, involving nitrifying bacteria for converting ammonia into nitrates. The drip hydroponic system is a type of hydroponic system where water and the nutrients are supplied to the plant roots slowly by drip irrigation. Water is supplied in slow drips so that the plant roots are kept moist but not over watered. This method reduces water evaporation as the water is slowly being dripped and also water wastage by leaching or run off. In drip hydroponic systems, there is control over how much water needs to be supplied for the plant. Finally the aeroponic systems are a specialized version of hydroponics where the roots of the plant extend only in air and the roots are directly sprayed with nutrient water. Water use is 25% less with aeroponics than other methods of hydroponics. Also fewer nutrients required since it is gently misted with nutrient-rich water rather than washed over the roots. These different systems are interchangeable, but some systems may be better for growing different types of plants.

Hydroponics technology can change the Indian agriculture industry. The word hydroponics comes from two Greek words – hydromeaning water and ponos meaning labour. This word was first used in 1929 by Dr William F Gericke, a California-based professor who began to develop a laboratory technique into a commercial means of growing plants. The US Army used hydroponic culture to grow fresh food for troops stationed on infertile Pacific islands during the World War II. By the 1950s, there were viable commercial farms in America, Europe, Africa and Asia. Plants mostly grown in hydroponic systems are tomatoes, bell pepper, cucumber, strawberries, watermelon, potato, onion, lettuce and all other leafy vegetables.

The advantages of hydroponics are faster growth with greater production, less sicknesses, less insect damages, elimination of soil-related insects, fungi and bacteria, much higher crop yields, no weeding and intercultural operation required, ideal for small spaces. Moreover, in this technology we have more control over the plants. But there are some disadvantages like the high initial and operational cost than soil culture. Also, skill and knowledge are needed to operate properly.

The hydroponic technology may never replace conventional farming, but with increasing population, this type of urban agricultural technology have started getting more demand in urban areas. Also we may see a new generation of modern farmers building green walls inside their houses to feed families with fresh produce, grown all year round.