Last edited 24 Feb 2021


The name 'potash' is given a range of salts containing potassium (typically oxides, sulphates, chlorides and carbonates) which occur naturally in the earth's surface and, being water-soluble, are subject to a natural, continuous 'recycling' processes. These compounds can be added to fertilisers.

Expressed notionally as K2O, typical compounds referred to potash include:

  • Potassium carbonate.
  • Potassium chloride.
  • Potassium sulphate.

The name potash derives from ‘pot ashes’ – the traditional method of manufacture. This involved leaching wood ashes in a pot then evaporating out the water from the solution to leave a white residue. It was recognised for its fertilising properties but was also used in the manufacture of soap, glass and gunpowder.

Potash also occurs naturally. It is the seventh most common element in the earth’s crust, buried deep below the surface. It is therefore deep-mined and is now the source for all commercially-available sources of potash – usually supplied in granular form. These deep-lying deposits have resulted from natural cycles of leaching and evaporation.

Some clays are naturally very rich in potassium and can contain as much as 17% potash; sea water globally also contains huge amounts of potassium.

[edit] Applicaions

The main uses of granulated potash include:

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