Hydroponics began in the 1930’s in the USA as an outgrowth of the culture techniques used by plant physiologists in plant nutrition experiments in the USA. It did not begin with the Hanging Gardens of Babylon as many might incorrectly pre-suppose. There were no compound chemicals available then and at best the Hanging Gardens were a series of cleverly constructed water channels down which the water flowed thus watering all the plants in soil based systems from top to bottom.
Hydro – Greek for water and ‘ponos’, meaning work, gives us the sense that hydroponics means to work in water. In a nutshell the basic difference between hydroponics and traditional soil based agriculture lies in the fact that in hydroponics the nutrient food for the plants comes from water soluble nutrients whereas in agriculture the nutrients come from the soil. Thus hydroponics can be said to be the growing of plants in nutrient solutions, with or without sand, gravel or other inert medium to provide mechanical support. In hydroponics there is no soil.
Having established that fact one might be tempted to assume that hydroponics is a much simpler way of growing plants than growing in the soil, but this is not totally true. Hydroponics is a meld of chemical engineering and agriculture together and apart from nutrition other aspects such as pest and diseases, and the preferences of the plant for more or less light remain the same.
How Hydroponics works
Plant nutrition in hydroponics is based upon the premise that all the nutrients that are required for the plant’s growth throughout its life cycle will be supplied in the same proportions that the plant will take up. Developmental science has established that there are 16 different elements that need to be supplied to the plant to maintain growth, development and survival, or put another way, for foliar development, flowering and fruiting. These elements are divided into 6 macro nutrients (where the minerals are absorbed in large quantities) 7 micro nutrients (where the minerals are absorbed in minute quantities) and three gases.
Minerals are measured in parts per million (ppm’s) and these are expressed in grams per million cubic centimetres of water. 1m cc’s of water is 1 Litre so ppm’s = g/L in the case of macro nutrients and milligrams (one thousandth of a gram) per 1m cc’s water in the case of micro nutrients or mg/L. Developmental science has established certain bandwidths within which the minerals should fall and they are broadly as follows:
ELEMENT – Parts per million bandwidths
Nitrogen (N) 100 – 450
Phosphorous (P) 10 – 100
Potassium (K) 100 – 750
Magnesium (Mg) 20 – 95
Calcium (Ca) 70 – 350
Sulphur (S) 20 – 250
Iron (Fe) 1 – 6
Manganese (Mn) 0.8 – 4
Boron (B) 0.3 – 0.8
Zinc (Zn ) 0.2 – 0.5
Molybdenum (Mo) 0.05 – 0.2
Copper (Cu) 0.05 – 0.1
Chlorine (Cl) 0.01 – 0.02
Perfect nutrition results in perfect plants.
The reason for such precision in the balance of nutrients is to avoid toxicity or deficiency in the nutrient mix.
Thus, contrary to what occurs in soil, the plants are supplied in just the correct proportions that they need resulting in perfectly balanced nutrition, the exact requirements of the plant resulting in optimal growth and high quality produce. If the produce is perfect then so are the availability of vitamins and minerals also at their maximum. In soil and organic growing the plant nutrients are not perfectly balanced often resulting in poor nutrition and slow growth. Yields are reduced and growth is stunted with consequent attacks by pests and diseases as they always attack a weak plant first.
When growing in soil, farmers must have their soils analysed to establish what minerals are missing and add lime to them to balance the pH level and fertilisers to fill in the missing minerals. Completely balanced nutrient levels are not always possible when farming in soil.
Most fertiliser companies supply their nutrient mixes in the form of a cocktail or blend of nutrients containing all the minerals except Calcium Nitrate which is supplied separately. This is to prevent the Calcium and Sulphur reacting together and forming Calcium Sulphate which sets up like epoxy when mixed together in concentrated form.
pH measures the number of Hydrogen ions present in a solution and is important in Hydroponics because the minerals are absorbed by the plant more readily when the pH is between 5.5 and 6.0 (7.0 is neutral). A hydroponic enthusiast should get a hand held pH and EC meter combined – Hanna instruments make a good one.
It’s important, before starting a hydroponic venture, to get a proper education in hydroponics. This will save you a lot of money and prevent you from making costly mistakes. DaisyFresh holds monthly 2-day courses in Camperdown outside Durban.
Hydroponics came into its own during WW2 when the US forces fighting in the South Sea Islands grew fresh vegetables hydroponically using the pristine white sand and the crystal-clear water of the volcanic islands.
Advantages to growing hydroponically:
– It uses less than 25% water compared to traditional agriculture
– There is no soil so therefore no digging, ploughing, fertilising, liming
– It can be used where the soil is not fertile such as on rocky terrain or poor infertile soils not conducive to successful growing
– When used with Verti-Gro, vertical hydroponic growing systems, it uses one sixth of the space compared to soil-based agriculture- yields are better due to perfect nutrition and fewer pests and diseases (no soil-based pests for example)
– Quicker turnaround time required- Clean produce does not require washing
– Longer shelf life
Learn everything you need to know and get all the tools you need to get your hydroponics growing!
Article source: www.hydroponicssouthafrica.co.za
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