Most plants and animals require certain mineral ions in order to live; these are classified as either macroelements or micro elements. Since animals easily consume these minerals through food, macroelements and microelements usually refer to these elements in conjunction with plants and gardening. With plants, these elements must be dissolved in the soil in order to be consumed.
Elements that a plant needs in large amounts to live are known as macroelements. Most often, access to macroelements is not a problem, but some occur in only limited amounts in the soil. Elements that are most limited in the soil are nitrogen, phosphorus and potassium, though these are the most prominent ingredients in most plant fertilizers.
Mineral elements that are needed by plants in only trace amounts are known as microelements. These elements are as important to a plant's health as macroelements, but needed in lower quantities. Many of the microelements are enzyme cofactors, which are easily supplied through the soil since only trace amounts are needed.
Mineral deficiencies are serious threats to a plant's health, and often produce visible symptoms. Most often, the growth of a plant is stunted, which is often attributed to nitrogen deficiencies and phosphorous deficiencies. Chlorosis, or the degradation of chlorophyll, is often caused by magnesium, iron and nitrogen deficiencies. Similarly, necrosis, or dead spots, is often caused by magnesium, potassium or manganese deficiencies.
The minerals classified as macroelements are carbon, hydrogen, oxygen, nitrogen, phosphate, sulphur, potassium, calcium and magnesium. These minerals should be supplied through fertilizers to ensure the maximum health of a plant. On the other hand, the microelements are iron, copper, manganese, boron, molybdenum, zinc and chlorine. These elements are not usually necessary in plant fertilizers, and too much can harm the growth of a plant.