Required Minerals

In addition to these three elements, a number of minerals-twelve to be exact-are essential to the welfare of plants. The majority of these are found dissolved in water in the soil: phosphorus, sulphur, calcium, potassium, magnesium, iron, zinc, manganese, copper, boron, and molybdenum are all taken into the plant through the roots. Nitrogen, the twelfth mineral, may be supplied by the atmosphere, yet it is taken in through the roots in a changed form. Because plants must take in minerals through the roots, nitrogen as an element is not available to a plant. In order to be used by the plant, nitrogen must therefore be converted to nitrate.

Some plants also require cobalt. Calcium is not required by certain fungi and algae.