How to feed plants

Plants need a wide range of elements, or nutrients, to survive. While they need different quantities of each one, a deficiency in any one of the nutrients can reduce the plant’s ability to function. Plants obtain most nutrients from the soil and absorb them as they take up water. In the cases of oxygen, carbon and hydrogen, the plant obtains these nutrients from the atmosphere (in the form of carbon dioxide and oxygen) and from water.

Below is a list of the nutrients plants require and what they are needed for:

Nutrient (element) Used in…*
Oxygen (O) Photosynthesis
Carbon (C) Photosynthesis
Hydrogen (H) Photosynthesis
Nigtrogen (N) Chlorophyll
Amino acids
Nucleic acid
Phosphorous (P) ATP (the compound which carries energy around the plant)
Nucleic acid
Potassium (K) Opening and closing the leaf stomata
Activating enzymes
Calcium (Ca) Cell wall structure
Enzyme cofactor
Magnesium (Mg) Chlorophyll
Activating enzymes
Sulphur (S) Proteins
Amino acids
Chlorine (Cl) Probably essential for photosynthesis
Osmosis and ionic balance
Iron (Fe) Chlorophyll
Boron (B) Enables use of calcium within the plant
Nucleic acid synthesis
Manganese (Mn) Activating some enzymes
Zinc (Zn) Enzymes
Activating enzymes
Copper (Cu) Enzymes
Activating enzymes
Nickel (Ni) Enzymes
Molybdenum (Mo) Enables use of nitrogen within the plant

* We have included some of the main uses for each of the nutrients, however this is by no means an exhaustive list.

A ‘balanced’ fertiliser contains an equal proportion of nitrogen, phosphorous and potassium, often expressed as NPK 1-1-1. Often balanced fertilisers will also contain other nutrients.

To increase nutrient levels, fertilisers or other sources of nutrients can be used:

Types of fertilisers available

Application methods

Example sources of nutrients