Essential Plant Nutrients

Plants require 16 essential elements for growth: carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P), potassium (K), sulfur (S), calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), boron (B), molybdenum (Mo), and chlorine (Cl). These 16 essential elements, also called nutrients, are often split into two groups. Plants obtain carbon (C), hydrogen (H), and oxygen (O) from air and water. Growers do not need to provide these nutrients, so they are not sold as fertilizers. The other 13 essential are provided by fertilizers.


Macro nutrients are nitrogen, phosphorus, and potassium. These nutrients are required by plants in the greatest amounts compared to the rest. These are the nutrients that are displayed on the front of fertilizer products such as 13-13-13... 13%N 13%P 13%K

  • It is absorbed by plants in two major ionic forms: Nitrate (NO3) and ammonium (NH4+)
  • Nitrogen is a part of all living cells and is a necessary part of all proteins, enzymes and metabolic processes involved in the synthesis and transfer of energy
  • The most recognized role of nitrogen in the plant is its presence in the structure of protein molecule
  • Nitrogen is a part of chlorophyll, the green pigment of the plant that is responsible for photosynthesis
  • Essential for plant cell division, vital for plant growth
  • Aids in production and use of carbohydrates
  • Affects energy reactions in the plant
  • Phosphorus is absorbed primarily as the monovalent inorganic phosphate anions (H2PO4)
  • Involved in photosynthesis, respiration, energy storage and transfer, cell division, and enlargement Promotes early root formation and growth
  • Major constituent of the energy transfer molecule ATP
  • Involved in the formation of oils, sugars, and starches
  • Helps early root growth and helps to establish seedlings quickly
  • Increases water-use efficiency
  • Encourages Blooming and Fruit Growth
  • Regulation of water in plant cells
  • More than 60 enzymes require K for their activation
  • Plays an important role in photosynthesis and translocation of photosynthates
  • Helps in the formation of proteins and chlorophyll
  • Carbohydrate metabolism and the break down and translocation of starches
  • Increases water-use efficiency
  • Essential to protein synthesis
  • Increases disease resistance


The secondary nutrients are calcium, magnesium, and sulfur. For most crops, these three are needed in lesser amounts that the primary nutrients.

  • Absorbed is absorbed as divalent Ca2+
  • Essential part of cell walls and required for the formation of new cells
  • Utilized for Continuous cell division and formation
  • Involved in nitrogen metabolism
  • Reduces plant respiration
  • Aids translocation of photosynthesis from leaves to fruiting organs
  • Increases fruit set
  • Stimulates microbial activity
  • Magnesium is absorbed as divalent Mg2 +
  • Key element of chlorophyll production. 15-20% of Mg remains in chlorophyll
  • Improves utilization and mobility of phosphorus
  • Activator and component of many plant enzymes
  • Increases iron utilization in plants
  • Influences earliness and uniformity of maturity
  • Sulphur is taken up by the plants from the soil as divalent sulphate anions (SO42-)
  • Essential for production of protein
  • Promotes activity and development of enzymes and vitamins
  • Helps in chlorophyll formation
  • Improves root growth and seed production
  • Helps with vigorous plant growth and resistance to cold
  • Aids in seed production
  • Necessary in chlorophyll formation (though it isn’t one of the constituents)


The micronutrients are boron, chlorine, cooper, iron, manganese, molybdenum, and zinc. These elements are used in very small amounts, but they are just as important to plant development and profitable crop production as the major nutrients.

  • Plants take up Fe as the ferrous (Fe2+) cation
  • Iron is a component of many enzymes associated with energy transfer, nitrogen reduction and fixation, and lignin formation
  • Important part of enzymes and aids in protein synthesis, photosynthesis and the metabolic functions of plants Promotes formation of chlorophyll
  • Acts as an oxygen carrier
  • Reactions involving cell division and growth
  • Manganese functions primarily as part of enzyme systems in plants
  • It activates several important metabolic reactions and plays a direct role in photosynthesis
  • Manganese accelerates germination and maturity while increasing the availability of phosphorus (P) and calcium (Ca
  • Helps photosynthesis and the metabolic functions of plants
  • Manganese helps in chlorophyll formation
  • Zinc (Zn) is taken up by plants as the divalent Zn+2cation
  • High yields are impossible without it
  • Aids plant growth hormones and enzyme system
  • Zinc influences the formation of some growth hormones in the plant
  • It is involved in auxin metabolism
  • Necessary for chlorophyll production
  • Necessary for carbohydrate formation
  • Necessary for starch formation
  • Aids in seed formation
  • Copper (Cu) activates enzymes and catalyzes reactions in several plant-growth processes
  • The presence of copper is closely linked to Vitamin A production, and it helps ensure successful protein synthesis
  • Acts as a catalyst in photosynthesis and respiration
  • It is a constituent of several enzyme systems involved in building and converting amino acids to proteins.
  • Important in carbohydrate and protein metabolism and formation of lining in plant cell walls.
  • Affects the flavor, the storage ability, and the sugar content of fruits
  • It helps in the utilization of iron during chlorophyll synthesis
  • Increases sugar content
  • Intensifies color
  • Improves flavor of fruits and vegetables 
  • Boron (B) exists taken up by plants as the BO33- anion
  • B supports the structural and functional integrity of plant cell membranes
  • Assists in the metabolic function of plant and aids in cell division
  • Increases the mobility of calcium in the plant
  • Acts as a regulator of K/Ca ratio in the plant
  • Required for the development of new cells in meristematic tissue
  • Necessary for proper pollination and fruit or seed setting
  • Essential for seed and cell wall formation
  • Promotes maturity
  • Necessary for sugar translocation
  • Essential component of the major enzyme nitrate reductase in plants
  • A structural component of nitrogenase, the enzyme actively involved in nitrogen fixation by root-nodule bacteria of leguminous crops, by some algae and by free-living nitrogen fixing bacteria
  • Reported to have an essential role in iron absorption and translocation in plants
  • Aids in the formation of legume nodules
  • Needed to convert inorganic phosphates to organic forms in the plant
  • Plants take up chlorine (Cl) as the chloride (Cl-) anion
  • Active in energy reactions in the plant
  • Not much information about its functions
  • Can interfere with P uptake
  • Enhances maturity of small grains on some soils