Cannabis Science


The Essential Role of Micronutrients in Cannabis Plant Development

Classifying a nutrient as essential for plant development requires three conditions:

1 . The nutrient must be directly involved in some manner with plant nutrition. 

2 . The plant would die without the presence of the nutrient.

3 . The nutrient is unique, meaning no other element can perform the same duties within plant development. 

When talking about essential nutrients for cannabis plant development, nitrogen, phosphorus, and potassium come to mind. These three primary macronutrients play distinctive roles as the plant progresses through its life cycles. While NPK ratios change during different growth periods, all three are necessary throughout a marijuana plant’s life.

Equally vital secondary nutrients, calcium, magnesium, and sulfur, each have critical roles in the complex plant development cycle from seed to harvest. In fact, many cannabis nutrient companies formulate Cal/Mag products as these two nutrients work favourably together.

Most growers generally turn to one of the primary or secondary nutrients if their cannabis plant shows signs of a deficiency or an overload. However, taking a closer look often reveals a lack of one or more vital micronutrients in the plant’s diet.

These lesser recognized trace minerals may seem like small potatoes compared to the macro and secondary nutrients simply because their contributions are on a much smaller scale.

Typically, they constitute less than 1% of the dry weight, and their physical input is in minimal quantities. However, each micronutrient has an essential role in cannabis plant development.

This article looks at each of the vital micronutrients a cannabis plant requires for optimal plant development and some symptoms of nutrient deficiencies a grower might encounter.

Boron (B)

Boron is a favourable contributor to cannabis plant growth. This functional element supports the structural integrity of cell membranes, helping to strengthen branches, stems, and foliage. Interestingly, B is very mobile in soil, moving into the plant’s root system as the borate anion BO3-3.

From there, it passes through the xylem during transpiration but otherwise is mostly immobile. Therefore, a steady diet of this necessary micronutrient is needed to support cellular activity. Boron is essential during all plant stages, particularly as the plant progresses from the vegetative phase into the flowering stage. It contributes to maturation, helping to structure cell walls for bud development.

While boron deficiencies are rare, it is easy to distinguish if a cannabis plant needs a B boost. New emerging leaves begin displaying distorted, twisted growth. In addition, they often become stunted, exhibiting brown or rust-coloured spotting. Boron deficiencies arise in drought conditions or if the substrate dries out frequently.

Chlorine (Cl)

Marijuana growers using plain tap water on their plants don’t have to worry about adding chlorine to a nutrient formula because most domestic water supplies already contain this essential micronutrient. In fact, many growers worry more about chlorine toxicity. However, cannabis plants need Cl to help transport ions and nutrients throughout the plant’s internal system.

Chlorine pairs up with potassium, increasing cellular osmotic pressure, which regulates the opening and closing of plant stomata. Furthermore, the crucial element helps regulate the hydration of plant tissue while assisting in oxygen flow, essential for cellular mobility in the plant’s root system and foliage.

While chlorine deficiencies are rare when applying tap water to marijuana plants, growers using reverse osmosis (RO) systems will need to add a small amount of this vital micronutrient to ensure plant health. Pale, wilting leaves are a sure sign of a chlorine deficiency. New growth will turn a light bronze colour before they shrivel up and die.

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Copper (Cu)

This powerful micronutrient spurs enzymes to support the functions of photosynthesis. Helping to catalyze reactions for carbohydrate and protein synthesis, copper speeds up chemical reactions. For example, copper activates enzymes responsible for the synthesis of lignin, the supportive tissues that produce the woody substance used to stiffen plant cell walls.

Furthermore, copper is linked to vitamin A production, boosting a plant’s immune system. Without this immobile nutrient, chloroplasts responsible for the green colour in plants could not function. Copper is a powerful influence on cannabis plant development. Without it, the plant will begin showing signs of distress quickly.

A marijuana plant will signal when it needs more Cu by displaying droopy leaves right after watering. Decreased copper levels reduce lignin enzymatic activation, diminishing a healthy plant’s structural stability. Moreover, the leaves will turn a hauntingly blueish-purple colour with bright white tips indicating the deficiency. Once a marijuana plant’s structural integrity and immune system are compromised, the door is wide open for botrytis, powdery mildew, and other fungi to come in.

Iron (Fe)

Think of iron as a fortifier for cannabis plant growth. This essential nutrient contributes to enzyme formation associated with the transfer of energy during photosynthesis. In addition, iron promotes chlorophyll production, helping turn light energy and carbon dioxide into the sugars the marijuana plant needs to survive.

Fe works synergistically with copper and other micronutrients, playing a distinct role in lignin production to build a robust support system. Without this mighty trace mineral, nitrate and sulfate molecules cannot reduce into ionic compounds readily available for plant uptake.

Because of its’ contribution to chlorophyll production, recognizing an iron deficiency is easy to see by the lack of green in the leaves. Instead, they turn bright yellow on new growth, except for the veins. As a plant cannot survive long without chlorophyll production, it will quickly respond with an abundance of neon yellow leaves throughout its branches.

Manganese (Mn)

Manganese is a powerhouse in cannabis plant development, assisting nitrogen and iron in the creation of chlorophyll. Supporting the systems and functions within the plant species, Mn activates enzyme activity to uphold the chloroplast membrane system.

As manganese stands guard to protect the root system, it encourages root cell elongations while building immunity to dangerous underground pathogens. As a bonus, this vital element directly contributes to both photosynthesis and respiration through the transfer of electrons in the oxidation-reduction process.

Because of this trace element’s aid in nitrogen absorption, it is easy to tell when a marijuana plant is experiencing a manganese deficiency. While cannabis leaves often turn yellow when in duress, Mn deficiency is unique in that leaves begin to yellow on the outer edges first, gradually working inward toward the vein.

Cannabis grower examines role of micronutrients in marijuana plant

Molybdenum (Mo)

Molybdenum has several critical roles in marijuana plant development. First, it helps create two enzymes in nitrogen assimilation and reduction. The first enzyme breaks nitrate down into the nitrite form, followed by the second enzyme, which further reduces the nitrogen molecule into the plant-available form of ammonium. This activity helps form proteins and synthesizes amino acids within the marijuana plant.

Additionally, this little micro ambassador also helps change the plant’s growth development as it flips from the vegetative stage into the pre-flowering stage. Molybdenum plays a substantial role in boosting flower development. As one of the only mobile micronutrients, Mo is active in root development and seed germination.

Molybdenum deficiencies are rare, and as with most cannabis issues, show up in yellowing leaves. Mo is unique, however, as it displays yellow leaves toward the middle of the plant, unlike nitrogen deficiencies, where leaves on lower branches will become affected first.

Zinc (Zn)

To increase yields from a fine cannabis cultivar, make sure zinc is in the nutrient recipe. This essential trace mineral is a catalyst for forming enzymes responsible for protein synthesis. Zn also aids photosynthesis, converting carbohydrates to sugars. An interesting attribute is zinc’s presence in plant tissue which helps marijuana plants endure cold temperatures.

Working together with magnesium and manganese, Zn is a fundamental contributor to chlorophyll production. This vital trace mineral also assists in producing large amounts of the growth hormones, auxins, which stimulate growth regulation and internode elongation.

Due to its contributions in chlorophyll production, zinc deficiencies tend to affect new growth displaying signs of chlorosis with necrotic browning on leaf tips. In addition, without the assistance of zinc in auxin production, internodes become compact, showcasing a rosette form of tiny, distorted leaves cupped upwards.

Bring in the Micronutrients to Boost Cannabis Plant Potential

Marijuana is an easy plant to grow. Water it, feed it a good diet, and it will grow. However, to maximize the potential of an exquisite cannabis cultivar, growers must put forth quite a bit more effort.

An elemental diet of the macro and secondary plant nutrients in the correct formulations is undoubtedly required. But as revealed from this article, incorporating the essential micronutrients into a feeding program is necessary to bring out the best from a prized cannabis plant.

Post author
Charle Thibodeau
Charle’ Thibodeau is a freelance writer with almost a decade´s experience, specializing in cannabis content for the past two years. A strong motivation to educate, inform, and promote the culture surrounding this miraculous plant is her earnest mission.
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