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Hydroponic farming/water culture
The word ‘hydroponics’ is derived from two Greek words: ‘hydro’ – meaning water, and ‘ponos’ – meaning labour.
Hydroponics is a technology for growing plants in nutrient solutions (water containing fertilizers) with or without the use of an artificial medium (sand, gravel, vermiculite, rock wool, perlite, peat moss, coir or sawdust) to provide mechanical support.
Hydrophonics System in Vegetable production
Growth medium is the substitute for soil in hydroponic systems. The functions of growth medium are
1. To provide the roots with O2.
2. Bring the water and dissolved nutrients in contact with roots.
3. Anchor the plants so that they do not fall over.
Many different materials can be used as long as they provide the roots with O2, water and nutrients. All the nutrients plants need are dissolved in water and they are supplied to plants every day. Macro elements (N; P; K; S; Ca) are needed in substantial amounts, whereas plants need very small amounts of micro elements (Fe; Zn; Mn; Mg; Cu; Co, Mg).
It is necessary to use was specially formulated fertilizers. Fertilizers used for hydroponics are more pure (and expensive) than other fertilizers to prevent precipitation and blockages of the system.
Different hydroponic systems
Two different hydroponic systems are used to produce vegetables: the gravel flow or recirculating system and the open bag or drain to waste system.
1. In the gravel flow system, the nutrient solution is recirculated and the roots of the plants stand in a thin film of nutrient solution all the time. Gravel or sand is used most often as growth medium.
2. In the drain to waste (open bag) system, plants are grown in containers and nutrient solution is supplied to plants by means of a dripper, for up to 12 times per day. The number of irrigation cycles per day depends on temperature and the growth stage of plants. The crops in the drain to waste system grow tall and need to be trained and pruned so that they grow upwards as a single stem.
Characteristics 1. No soil is required. 2. Plants are irrigated automatically.
3. No water stress.
4. Nutrients are available at all times
5. Only soluble fertilizers are used.
6. Hydroponic fertilizer formulations contain a balanced nutrient content
7. Soil borne diseases can be eliminated
8. Hydroponic production is not organic because artificial nutrients are always used and plants are usually not grown in soil.
Advantages of hydroponic vegetable production
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.
