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Some useful information about

Hydroponic Nutrient Solutions.


Raw materials that make up the formula.

In hydroponics all the active ingredients used in the nutrient solution have to be 100% soluble in water.

The selection of the raw materials to be used depends on a number of factors.

1) The quantity of the ions in the selected raw material must be comparable with that required in the nutrient formula.

2) The solubility of the raw material is very important, since plants can only absorb nutrient elements that are totally dissolved in water. Calcium sulphate is a cheap source of calcium but, is almost insoluble, therefore the more expensive calcium nitrate is used. - In other words Calcium sulphate may be OK for use in the soil but not much use in hydroponic growing.

3) Do not be tempted to use a cheap grade of raw material. Some commercial fertilizer grades are suitable, however you may have to step up to technical or even food grade to provide some of the required ingredients. In any event it is suggested that before use, the purity of the materials be fully established, since an impurity, which may be of no consequence for use in soil growing can again lead to a toxicity of a trace element which could be fatal in hydroponic growing.

As an example of purity, common grades of Magnesium sulphate are quoted at 45% relative to active element required.

4) A low quality grade can also contain excessive insoluble, inert carriers such as clay or silt particles which will form a sludge and can block feeder lines and could also tie up other nutrients.

Here is a list of suitable raw materials.

Macro elements.

Raw material

Usual name


Potassium nitrate


Calcium nitrate


Mono potassium phosphate


Potassium chloride


Potassium sulphate


Magnesium sulphate


Calcium chloride


Calcium sulphate

Microelements (Trace Elements)

Raw material

Usual name


Iron chelate


Boric acid

MnSO4 4H2O

Manganese sulphate

CuSO4 5H2O

Copper sulphate

ZnSO4 7H2O

Zinc sulphate


Ammonium molybdate

Adjustment materials

Raw material

Usual name


Phosphoric acid


Nitric acid


Potassium hydroxide

Most popular and suitable compounds for nutrient solutions.

Macro elements.

Calcium is supplied by calcium nitrate, this also supplies a portion of the nitrates, any additional nitrogen should be supplied by potassium nitrate or with the use of Nitric acid in pH correction.

Potassium nitrate supplies a major portion of the potassium.

Phosphorous is supplied by potassium phosphate, this also supplies a portion of the potassium.

The balance of the potassium is supplied by potassium sulphate. This supplies a portion of the sulphates the majority of which is supplied by magnesium sulphate, while also supplying the magnesium required.

Micro elements.

The micro elements can be obtained as a premix from a commercial supplier as they save a considerable amount of trouble in weighing to the very accurate levels required. A commercial mix can be tailored to suit the water supply and the crop being grown.

If you wish to mix your own then use a blend containing:

Iron chelate, Boric acid, Manganese sulphate,Copper sulphate, Zinc sulphate and Ammonium molybdate.

Be aware

While there are some company’s who produce good ‘single mix’ nutrient formulas the basic chemical rule is that materials such as Calcium nitrate and Magnesium sulphate will react when brought into contact with one another and a chemical precipitation will take place with the result that the sulphate will exchange with the nitrate and form an insoluble compound ‘calcium sulphate’ who's common name is gypsum - this material is useless in a nutrient solution. In order to steer clear of such problems, most hydroponic nutrient formulas are supplied in two or more separate packs and the materials within each pack which could cause problems are kept completely apart until such time as they are diluted down to growing strength nutrient - at this very weak strength no chemical reaction will take place.

Refer to our page about the Vitaran nutrient formula calculator which enables you to optimise your own nutrient growing formulas tailored to suit the quality of your water supply










Hydroponic Developments - 7 Smiths Road - Tauranga - New Zealand - Ph +64 7 5769651

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