Nutrition at the Root of Plant Health

Seventeen Plant Nutrients You Need to Know

There is a delicate balance between too much of a good thing and not enough. Finding the optimum nutrient balance for maximum yield is a perpetual challenge for growers.

All plants require 17 essential nutrients for growth. Of these, three (carbon, oxygen and hydrogen) are absorbed through air and water; the rest come from the soil. Determining the proper amount of each required element is a true art, because so many factors come into play including soil pH, soil structure, weather, the species of plant, stage of development, application method, watering needs and other variables.

Of the 14 remaining nutrients, six are considered primary or secondary macronutrients and eight are micronutrients.

Primary Macronutrients

Primary macronutrients are usually depleted from the soil first because larger quantities are required by the plant.

Nitrogen — Nitrogen plays an essential part in plant growth. Considered the most important of all the essential nutrients, nitrogen plays a critical part in the formation of amino acids that build the proteins that make up plant tissue. It is also in chlorophyll where photosynthesis takes place and is vital to that process.

Phosphorous — Also an important element in photosynthesis, phosphorous is involved in many essential plant processes, including cell enlargement and division, respiration and the storage and transfer of energy. It enhances flower, fruit and root production.

Potassium — Potassium is also required in large amounts by plants; in most cases in quantities second only to nitrogen. It is essential for protein synthesis and in the production of starches and sugars. Adequate amounts of potassium improve fruit quality and help plants resist stress.

Secondary Macronutrients

Secondary macronutrients are needed in lesser quantities than the primary nutrients, but are no less important.

Calcium — Calcium is a vital ingredient in the formation of plant cell walls and also aids in the transport of other nutrients within the plant.

Magnesium — A key component of chlorophyll, magnesium plays a part in activation of many plant enzymes and in cellular respiration.

Sulfur — Sulfur is an important building block in some amino acids, and therefore is essential in protein formation as well as in production of chlorophyll. It promotes root growth and aids in resistance to cold.


Micronutrients are only needed in very small or even trace amounts by plants, but are still essential for growth.

Boron — is essential for the formation of pollen, and therefore is vital to seed and fruit production. It helps the plant produce sugar and other carbohydrates and use other nutrients.

Chlorine — helps the plant maintain leaf turgor and photosynthesis, and helps plants handle water stress. It may help some plants resist fungal diseases.

Copper — Copper is a catalyst for chemical reactions within the plant, aiding in plant metabolism and in the formation of protein pigments.

Iron — Iron is also a catalyst and is especially important in the manufacture of chlorophyll. It is also important in plant respiration and regulation of enzymes.

Manganese &mdash Manganese is important in chlorophyll formation and regulation of plant enzymes.

Molybdenum — Molybdenum helps plants make better, more efficient use of nitrogen and photphorus. It is also needed by legumes for nitrogen fixation.

Zinc — Zinc is vital to stem elongation and in the formation of growth hormones, proteins and starches.


Fertilizer 101
Plant Nutrient Functions and Deficiency and Toxicity Symptoms, Montana State Univ. Extension, Ann McCauley, Clain Jones, Jeff Jacobsen
Plant Nutrients