An Introduction to Hydroponics

An Introduction to Hydroponics

Dr. Hannah Krujia
SMS Agronomy, KVK Phek

The science of soil-less gardening is called hydroponics. It basically involves growing healthy plants without the use of a traditional soil medium by using a nutrient like a mineral rich water solution instead. Hydroponic plant requires selected nutrients, some water, and sunlight to grow. Not only do plants grow without soil, they often grow a lot better with their roots in water instead. Hydroponic gardening is fast becoming a popular choice for many growers around the world due to its more sustainable approach to resource usage than the usual growing methods.


The Nutrient Solution

One can make one’s own special solutions for different types of crops based on the chemical elements the plants need most. The right nutrient mix combines primary nutrients (nitrogen, potassium and magnesium), secondary nutrients (calcium, sulphur, phosphorus) and micronutrients (iron, copper, manganese, zinc, molybdenum, boron). The recipe for a basic nutrient solution that we can make ourself is by diluting the nutrients in 20 litres of filtered water.
• 25 ml of CaNO3 (calcium nitrate)
• 1.7 ml of K2SO4 (potassium sulfate)
• 8.3 ml of KNO3 (potassium nitrate)
• 6.25 ml of KH2PO4 (monopotassium phosphate)
• 17.5 ml of MgSO4 (magnesium sulfate)
• 2 ml of trace elements


After preparation of the solution, store the solution in a food-grade container at room temperature and away from sunlight. Make sure to shake it well before using. Also, the plants will indicate if they are receiving too few or too many nutrients such as if there is deficit in nutrients the leaves will turn yellow, if too much and they will look brown, burnt or curled.


A hydroponics system

Hydroponics systems are various structures (e.g., towers, trays, A-frames) that hold water or other inert media and provide places to grow plants. Hydroponics systems fall into two basic categories: a solution (liquid) culture and an aggregate culture. In a solution system, the plant roots grow directly into a nutrient-filled solution. In an aggregate system, such as gravel, sand, or small clay pellets, the roots grow into the medium. In each method, the system supplies the three essential ingredients plant roots need to grow: water/moisture, nutrients and oxygen. Different types of systems are available to meet individual comfort levels in growing plants hydroponically. These include drip, ebb and flow, nutrient film technique, water culture and aeroponics.


While one can grow almost anything hydroponically, some vegetables thrive more in hydroponic systems than others. Choose plants that require moisture such as cucumber, tomato, capsicum, strawberry, lettuce and leafy greens. Also, when setting up a hydroponic garden, depending on the size, sturdiness and root development of the plants to be grown and the structure of the system, one needs to decide whether to use only a solution culture or some sort of a growth medium. Plants with shallow roots, like leafy greens, do fine in solution cultures. On the other hand, plants with deep roots, such as beets, and heavy vegetables, such as cucumbers, do better with growth mediums such as foam, coconut husk, sponges, and peat moss. Also, flowering and fruiting plants need exposure to sunlight while leafy greens grow well even under inexpensive fluorescent lights that are placed above them.


Advantages of hydroponic crop production
• Hydroponically produced vegetables can be of high quality and need little washing.
• Soil preparation and weeding is reduced or eliminated.
• It is possible to produce very high yields of vegetables on a small area because an environment optimal for plant growth is created. All the nutrients and water that the plants need, are available at all times.
• One does not need good soil to grow vegetables.
• Water is used efficiently.
• Pollution of soil with unused nutrients is greatly reduced


Disadvantages of hydroponics
• Hydroponic production is management, capital and labour intensive.
• A high level of expertise is required.
• Daily attention is necessary.
• Specially formulated, soluble nutrients must always be used.
• Pests and diseases remain a big risk.
• Finding a market can be a problem.