Hydroponics is considered to be a type of hydroculture. It is a technique that contributes to the growth of plants. It uses a wide range of mineral nutrients without the use of soil for cultivation. Fish waste, duck manure and other normal nutrients are the main sources of nutrients in hydroponics. This article aims to discuss hydroponics and will focus on its requirements, types and significance in detail.

What is Hydroponics?

The type of horticulture technique that involves growing plants without soil, using an aqueous solution of minerals is called hydroponics. The word “Hydroponics” is derived from the word “hydros” meaning water, and “ponos” meaning toil or labour. Literally, it means working water. In simpler terms, hydroponics means growing plants without soil.

Plants can be grown with their roots immersed in mineral solution only, or they can be grown using an inert medium like perlite, vermiculite, gravel, sand, rice husk, coconut coir or other substrates. The nutrients required for hydroponic systems can be obtained from fish excrement, duck manure, chemical fertilizers or artificial nutrient solutions.

Fig: Hydroponic Vegetable Being Observed

History of Hydroponics

1. The earliest published work on growing plants without soil was done by Franscis Bacon in \(1627\) in a book called Sylva sylvarum (A Natural History).
2. In \(1699,\) John Woodward published his water culture experiments with spearmint.
3. German botanist Junlius von Sachs and Wilhelm Knop experimented and found out that \(9\) elements are most essential for plant growth. They developed a technique of soilless cultivation.
4. In\(1929,\) William Frederic Gericke started promoting soilless culture for agricultural crops.
5. In \(1937,\) Frederic Gericke coined the term hydroponics and the majority of the work in the area of hydroponics is credited to him.
6. Denis Rober Hoagland experimented extensively for the formulas of minerals in the solution and developed the universal Hoagland solution.
7. Daniel Arnon also experimented and developed formulas for mineral solutions. The combined mediums are now known as Arnon-Hoagland medium.
8. In recent decades, NASA has done extensive research on hydroponics for its Controlled Ecological Life Support System.

Requirement of Hydroponic System

Hydroponics uses the aqueous solution of minerals or some sterile medium like perlite or vermiculite, etc., to facilitate the growth of plants. The basic principle of hydroponics is that if plants are supplied with the required minerals in precise quantities, then plants grow vigorously to their genetic potential.

There are multiple approaches to design hydroponic systems, but the basic requirements remain the same. The basic requirements of hydroponics are:

1. Freshwater: Most plants grow in freshwater with a pH in the range of \(5.5\) to \(6.5,\) and this can be adjusted using simple garden solutions and crop requirements.
2. Oxygen: In traditional farming, roots obtain oxygen from the air pockets of the soil. In a hydroponic set-up, depending on the design, one either needs to leave a gap between the growing medium and roots or aerate the nutrient solution for sufficient oxygen.
3. Root support: Although the hydroponic system is a soil-less system, plant roots are immersed in an inert medium for support. A few examples of such inert media are perlite, vermiculite, rock-wool, coconut coir, rice husk, gravel etc. Compact materials with less aeration are avoided.
4. Nutrient solution: Nutrient solutions are balanced for the micro-elements and macro-elements that the plants require.
5. Light: Light requirements for photosynthesis and growth of each plant differ and this needs to be taken into account while using artificial light.

Types of Hydroponic System

The basic needs of plants for growth are mineral nutrients, water and oxygen, which are supplied to plants in various ways depending on the design of the hydroponic system. There are \(6\) types of hydroponic systems. They are as follows:

1. Wick System: It is the simplest system of doing hydroponics which does not require electricity, pump and aerator. Plants are placed in an inert medium like perlite,  and then the nylon wicks positioned around the plant are dropped down into the nutrient solution. Thus, the nutrient solution flows to the plant roots through the wicks.  This is an economic method ideal for smaller plants.

Fig: Wick Type Hydroponic System

2. Deep Water Culture System: In this type of hydroponic system, roots are placed directly into the nutrient solution. The oxygen that plants need is sent through an aerator. Plants are secured in their position using net pots. In this technique, nutrients are easily absorbed by the plants and can be adapted for any type of plant.

Fig: Deep Water Culture Type of Hydroponic System

3. Ebb and Flow System: It is a flood and drain system of hydroponics. In this system, plants are placed in a spacious grow bed with an inert medium like rock wool or perlite. Then the mineral solution is flooded until it reaches a couple of inches below the top surface of the medium to avoid overflow. Thus, the roots of the plants get immersed in the mineral solution.  After a certain time, the mineral solution is drained back using a pump. The pumps are automatic with timers and play an important role in this type of hydroponics.

Fig: Ebb and Flow Type of Hydroponic System

4. Drip System: It is an easy-to-use system and can be converted into other types quickly. The nutrient solution is pumped into a tube that sends it right to the base of each plant in a dripping manner. The tube is a drip emitter that controls how much solution is placed into the plant. This system can be small or large and circulating or non-circulating type.

Fig: Drip Type of Hydroponic System

5. Nutrient Film Technique (NFT): It is the most popular variant of continuous-flow solution culture where solution flows continuously past the roots.  The nutrient solution flows over the tick mat of roots that grow at the bottom of the watertight container. The upper section of the container has moist air, and hence that layer of roots gets an abundant supply of oxygen. A properly designed NFT system is based on using the right channel slope, the right flow rate, and the right channel length.

Fig: Nutrient Film Technique of Hydroponic System

6. Aeroponic System: In this system, plants are suspended in the air, and a couple of mist nozzles are fitted below the plant. These nozzles are connected directly to the pump and spray the nutrient solution on the roots of each plant. The excess nutrient solution that drains off the roots is collected in a reservoir placed below the plants. Since the plants are suspended in the air, they get all the oxygen that is required.

Fig: Aeroponic technique

Significance of Hydroponics

There are many benefits of plants growing hydroponically.

1. Growth and yield of plants is high.
2. Water and nutrient solutions can be used efficiently.
3. Weeds can be easily eliminated.
4. Hydroponic systems can be set up anywhere like rooftops, balconies, greenhouses, etc.
5. A hydroponic system facilitates micro-climate in a controlled environment.
6. Plants can be grown where traditional farming is not possible.
7. Organic food can be grown without using chemical fertilizers or pesticides.
8. Hydroponics is used extensively in space research programs where they can be grown in soil-less conditions. It can be used to grow food away from the earth where the soil is unavailable.

Why is Hydroponics Bad?

1. The initial investments are high.
2. It requires technical knowledge.
3. Constant monitoring is required.
4. Vulnerable to power outages.
5. Production is limited compared to field conditions.
6. Presently, it is applicable for a small range of plants, which have a small life cycle.

Summary

Hydroponics is a way to skip the soil dependency of plants. This technique was initially developed to study the mineral requirement of plants for their growth. In earlier days, hydroponics experiments were used to determine quantities of each element required for plant growth and assessed for its effect on plant growth. The requirement of macroelements and microelements essential for the growth of most plants were established. It was also assessed if hydroponic systems offered any advantage in terms of yields compared to the traditional ways of farming.

Today, hydroponics is used by home gardeners to space scientists and is a preferred way of growing vegetables and other food plants in situations like arid conditions, space programs and areas where traditional farming is not possible.

Frequently Asked Questions (FAQs) on Hydroponics

Frequently asked questions related to hydroponics is listed as follows:

Q.1. Where to buy hydroponics nutrient solutions?
Ans: Plants get carbon, hydrogen and oxygen from water and air. The remaining elements essential for their growth are absorbed from nutrient solutions, which can be obtained from commercial outlets.

Q.2. Where to set up a hydroponics system?
Ans: Hydroponics have 6 different designs or types, and depending on the space availability, anyone can be adapted. Generally, hydroponics farming is done in places like greenhouses, balconies, home gardens, rooftops, research laboratories etc.

Q.3. What is hydroponics?
Ans: The type of horticulture technique that involves growing plants without soil using an aqueous solution of minerals is called hydroponics.

Q.4. What are the types of Hydroponics?

Ans: There are \(6\) types of hydroponic systems, and they are:
1. Wick System
2. Ebb and Flow system
3. Deep Water Culture (DWC) system
4. Drip System
5. Nutrient Film Technique (NFT)
6. Aeroponic System

Q.5. What can be grown in hydroponics?
Ans: Almost any plants having a short life cycle can be grown hydroponically. But some most common food plants grown hydroponically are lettuce, spinach, strawberries, tomatoes, bell peppers, carrots, turnips, different types of herbs etc.

We hope this detailed article on Hydroponics helps you in your preparation. If you get stuck do let us know in the comments section below and we will get back to you at the earliest.