Calcined Magnesite is a Magnesium fertiliser containing 48% Magnesium [80% MgO] derived from Magnesium Oxide.

Because Magnesium Oxide is insoluble, it is calcined, that is, heated with lime at high temperatures, to release a little of the magniesium into plant-available form. It can be dusty and abrasive and thus not suitable for farmer application but can be blended with other materials, particularly salt, kainit or sylvinite to form a high quality product.

Even so, at pH's above 7.6, little magnesium becomes available to the plant from Calcined Magnesite. Granular Kieserite or Kainit [do not apply Kainit to potatoes] may be a better Magnesium fertilisation option.

If you cannot afford to have all the magnesium as Kieserite or Kainit, then we can easily make you a custom blend containing Magnesium from both CalMag, Kieserite and/or Kainit

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