Nutrients in Plants

What are the main nutrients in plants?  

There are 16 essential nutrients for plants and scientists have grouped them into three categories based on their importance.  

In the first category, known as macronutrients, there is carbon, hydrogen, nitrogen, oxygen, phosphorus and potassium. The second category contains calcium, magnesium and sulfur.  The third category, also known as micro- or trace nutrients are required in tiny amounts compared to primary or secondary nutrients. Micronutrients are boron, chlorine, copper, iron, manganese, molybdenum, and zinc. 

In order for a plant to use a nutrient, it must be in either a positively charged ion (cation) or a negatively charged ion (anion). A plant is not able to make use of any organic compounds unless they are broken down into ionic form.  

How to help plants get the right nutrients

There are natural ways that we can boost the level of nutrients in soil to optimize plant growth. 

Compost is a great way to ensure that plants are receiving a wide range of nutrients for optimal growth. Specifically, if the plants are low on potassium, consider adding banana peels. If the plants are low on calcium, adding eggshells can help address this issue. It is important to ensure that the compost is fully broken down so that the plants can actually absorb the nutrients.   


  • Mulch is a great way to ensure that plants do not have to compete with weeds, maintain nutrients and inhibiting erosion and water runoff.  

Winter time 

  • During the winter, it is important to leave the stems and roots of plants in the ground. The decaying plants help add nutrients to the soil and the root systems help hold the soil in place on windy days. Without the plants, much of the nutrients would end up blowing away.  

Wood Ash  

  • Wood ash is an excellent way to increase soils level of potassium. However, be careful to only add a minimal amount to not completely disrupt the natural balance.  

Nutrient deficiencies

Nutrient deficiencies are popular in plants and they can hinder the ability for plants to mature. There are different indicators of nutrient deficiencies. Some of these deficiencies can result in leaf discolouration, holes in leaves, stunted leaves, crop failure, and yellow or brown spots on leaves.  

Before any treatment, it is important to consider other factors that may be affecting the health of the plant.  

  • Check for signs of insects and diseases. Pests can leave discolouration or holes in the plant.
  • Check the water. Water quality has a large role to play in the success of the crops. If desired, you can send a water sample into a lab to have it analyzed.  
  • Watch the temperature of the growing environment. Large temperature changes or being consistently hot or cold can affect plant growth.  
  • Monitor pH levels. Every plant has a preferred level of hydrogen. If the soil is too acidic or alkaline, this will inhibit the growth of the plant.  

If all of the indicators above are in a desired range, consider calling in a professional to come and take a look. Remember that each plant species has desired levels of minerals, sunlight, soil and water. Ensure that you conduct research on the different types of plants that you are growing to have success.