Know your Grow!

Understanding Nutrients: Macronutrients vs Micronutrients

Knowing the conditions your cannabis plant is growing in is crucial during the process of growth. Cannabis, much like other vegetation, relies on soil, water, and air to provide the nutrients needed to grow strong and healthy. The growth cycle of a cannabis plant contains three stages; seedling, vegetative, and flowering. Each requires a specific ratio of macro- and micronutrients.  

Macronutrients are required in large quantities and are pivotal in the development of cellular components like proteins and nucleic acids. Nitrogen (N), phosphorus (P), potassium (K), calcium (CA), magnesium (Mg), and sulfur (S) are the main elements of macronutrients.  

Carbon (C), hydrogen (H), and oxygen (O) are also considered macronutrients; however, they are categorized as a non-mineral class of macronutrients. Plants absorb carbon dioxide (CO2) and water (H2O) from their environment. The amount of air and water, as well as the type of soil, that is available during this process is crucial. The water and CO2 obtained during this process is then turned into the carbon “backbones” of proteins, sugars, DNA and other biological molecules. The oxygen is then released into the air and the newly formed biomolecules support the plant’s development.  

Micronutrients are needed in smaller quantities and are necessary for enzyme activity, photosynthesis, and the uptake and transport of other nutrients. Iron (Fe), zinc (Zn), boron (B), copper (Cu), manganese (Mn), and molybdenum (Mo) are the main elements of micronutrients. 

Nutrient complications in the growth cycle will produce excessive amounts of stress and lead to adverse effects. Depending on the amount of excess nutrients or nutrients needed, the overall yield and end quality of the product are affected along with the health of the plant.  


Macronutrients are classified as either primary or secondary. Primary macronutrients, nitrogen (N), phosphorus (P), and potassium (K), are the main sources of everything from root development to flower production. Secondary macronutrients, calcium (Ca), magnesium (Mg) and sulfur (S), are needed in smaller quantities but have just as strong of an impact.  

Nitrogen’s primary role is to aid in protein development and the metabolism of energy, which is crucial for plant growth. Nitrogen also enhances the development of amino and nucleic acids which increase the production of proteins, DNA and RNA. It is also a key component of chlorophyll which produces a green pigment in plants and allows for energy to be converted through photosynthesis. Nitrogen is mainly needed during the vegetive stage where the plants primary focus is on the production of stems, branches, and foliage. If excessive amounts of nitrogen are present within the flowering stage, it can lead to abundant foliage growth which takes away vital nutrients needed for flower development. 

Phosphorus is critical for multiple essential processes including root development, enzyme activity, energy transfer, and flower formation. It is also involved in the process of photosynthesis by helping transport energy from the leaves to the rest of the plant. Phosphorus is needed during the flowering stage to help support strong and healthy flower formations. Phosphorus deficiency results in the leaves of the plant turning dark green and purple. Deficiency in this area results in reduced flower production and poor root development. Excessive amounts of phosphorus can lead to levels of toxicity, causing a build-up of salts in the soil. This interferes with the plant’s ability to absorb water and other nutrients. 

Potassium is the third primary macronutrient, mainly involved in the production of branches, stems, and flowers. Potassium helps regulate water intake, the development of plant tissues and helps build stress tolerance. This provides more resistance to periods of drought or other environmental stress. Potassium is necessary throughout the entire growth cycle to help support the development of a healthy plant. Deficiencies will cause the leaves of the plant to become yellow or brown around the edges and growth to be stunted. Lack of healthy plant tissues results in lower quality products and increased susceptibility to diseases and pests. 

Calcium provides essential components for root health and the growth of vegetation. The main responsibility is to provide structure for plant cell walls and help contribute to the overall stability of the plant. Calcium is also responsible for stimulating enzymes and preserving membrane permeability. This creates strong root structures and proper access to nitrogen and sugar all throughout the plant. Being one of the secondary macronutrients, calcium is needed in a lesser amount than the above components but holds just as important of a role.  

Magnesium and sulfur are core components in chlorophyll and are necessary for photosynthesis. Magnesium encourages the absorption and transportation of phosphorus while also performing as an enzyme activator. Magnesium activates more enzymes than any other nutrient. Sulfur improves nitrogen efficiency and allows for the metabolism of nitrogen. Disease resistance, formation of proteins enzymes, and amino acids are also enhanced due to sulfur.  

Each of the macronutrients work in unison to provide the plant with the support it needs to survive in its’ environment. Understanding elements like nitrogen, phosphorus and potassium, is essential to understanding plant growth and the overall health of a plant. Deficiencies in any of these areas will result in adverse effects and harm to the plants’ health. 


Micronutrients, or trace elements, are necessary for enzyme activity, photosynthesis, and the uptake and transfer of other nutrients. Iron (Fe), zinc (Zn), boron (B), copper (Cu), manganese (Mn), and molybdenum (Mo) are the main micronutrients. Even though they are needed in smaller quantities, their contribution to plant health and development is significant.  

Iron is crucial for chlorophyll production, photosynthesis and electron transport. Zinc aids in the development of plant growth hormones as well as increases in cellular numbers and cell expansion. It is also necessary for the development of chlorophyll as it helps to resist diseases and maintain responses due to stress. Boron is an essential element for seed and flower development. It also focuses on the production of cell walls and the growth of strong roots. 

Copper stimulates enzyme activity, protein synthesis, and respiration. Copper also assists in the metabolism of carbohydrates and proteins as well as the absorption of iron. Manganese encourages enzymes to properly function as well as the metabolism of carbohydrates and nitrogen. Manganese also builds stress tolerance and is crucial for seed production and root growth. Molybdenum is the main component in the process of nitrogen metabolism and the production of amino acids and proteins. Molybdenum interacts with enzymes to help convert nitrate into nitrite then nitrite into ammonia. This allows for the plant to properly absorb iron even further.  

Trace elements such as these are necessary throughout the entire grow cycle. Each element works together to build a solid foundation for exponential growth. They are mainly known for enzyme activity, photosynthesis, and intake of nutrients. Even though they are needed in smaller quantities, micronutrients are big components of any strong and healthy plant. 


Plant development and health rely on a combination of all the above macro- and micronutrients. These components contribute to enzyme activity, the ability to metabolize energy, uptake water and nutrients and the overall growth of the plant. Deficiencies in any one of these areas result in detrimental amounts of stress and will affect the plants’ health and end quality. Understanding the role nutrients play is necessary throughout the entire growth cycle. By considering the specific ratio of nutrients a plant needs, growers have the opportunity to optimize their plants’ health to the fullest extent. 

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Written by Veronica Martinez May 2023