For a cannabis plant to survive and thrive, it must have access to the essential elements. To be considered essential, an element must meet the following criteria: have a direct bearing on the completion of the plant’s life cycle; be required for a specific biological function; be required by a majority of plant species, and it cannot be replaced by another element. To date, scientists have identified 17 essential elements for cannabis plants.
The essential elements required for plant functions can be broken down into two categories: essential mineral elements and essential non-mineral elements. The essential mineral elements are absorbed by most plants through nutrient uptake in the root zone. Non-mineral elements (hydrogen, oxygen, and carbon) are either taken up as a gas or as water.
Essential Mineral Elements
The essential mineral elements needed to sustain plant growth are found in the soil or hydroponic solution. A cannabis plant’s essential mineral elements can be further broken down into two categories: macro- or micronutrients. Macronutrients are the nutrients used in higher concentrations relative to micronutrients, which are absorbed in smaller amounts. Most cannabis cultivators are familiar with the essential macronutrients, which include nitrogen (N), phosphorus (P), potassium (K), calcium (C), magnesium (Mg), and sulfur (S).
The term trace elements (or trace minerals) in horticulture refers to minerals whose concentration in the soil and living tissue of the plant is only found in trace amounts. Specifically, a trace element is an element whose concentration is less than 1,000 ppm in a soil sample. The trace elements that are essential for cannabis fall into the micronutrient category. Although trace elements and micronutrients are not technically interchangeable terms, in cannabis cultivation, they are widely referred to as the same thing.
Although many cannabis growers may already use fertilizer or balanced soil containing some, if not all, of the essential micronutrients, the names of these nutrients are generally less familiar to growers. Don’t let the name fool you — micronutrients, although used in lower amounts than macronutrients, play an equally important role in plant health and crop production. In fact, they are just as essential to a high-yielding cannabis crop as the macronutrients. The trace elements/micronutrients known to be essential for cannabis growth are boron, chlorine, copper, iron, manganese, molybdenum, nickel, and zinc. Each of these nutrients plays a vital role in the development and/or health of a cannabis plant.
Boron (B) — Essential for tissue growth within the plant. Promotes the absorption of water and helps regulate a plant’s metabolism. Boron also assists in the formation of fruit.
Chlorine (Cl) — Involved in the stimulation of photosynthesis.
Copper (Cu) — Plays a role in chlorophyll production and helps activate various enzymes.
Iron (Fe) — Assists in biochemical processes, including the manufacturing of chlorophyll. Iron also contributes to the formation of some enzymes and amino acids.
Manganese (Mn) — Plays an essential role in nitrogen assimilation and protein formation. Manganese can speed up a plant’s maturity and helps promote seed germination. Also necessary for chlorophyll production.
Molybdenum (Mo) — Needed for producing nitrogen-based proteins. Molybdenum is essential for nitrogen assimilation by plants.
Nickel (Ni) — Regulates mineral metabolism, enzyme activity, and other metabolic processes in plants.
Zinc (Zn) — Helps with the development of enzymes and growth hormones.
How to Supplement Trace Minerals/Micronutrients
When supplementing trace minerals to the soil, there are two sources that are readily available to cannabis gardeners. Perhaps the best choice for home cannabis growers is volcanic rock dust. Volcanic rock dust can be added to just about any soil recipe or top-dressed/amended as needed. The other commonly used supplement is sea minerals. Sea minerals are derived from dried seawater.
Many commercial farmers are choosing sea minerals over volcanic rock dust to restore the soil’s mineral balance. This is likely due to cost efficiency in large-scale applications. One possible concern for cannabis growers using sea minerals is the salt content and the potential negative impacts of accumulated salt. For that reason, I recommend volcanic rock dust to cannabis gardeners.
Beneficial Microorganisms/Trace Minerals as Enzyme Cofactors
Organic cannabis growers understand the power of living soil. A soil is considered living when it has a healthy population of beneficial microorganisms. These microorganisms have various functions that aid plant health. For example, enzymes produced by microorganisms are the catalysts for many chemical reactions in the soil, including nutrient uptake. Some soil microorganisms require specific elements to use as enzyme cofactors. A cofactor is a non-protein chemical compound that is required for the protein's biological activity. Many enzymes require cofactors to function properly. Cofactors can be considered molecules that assist enzymes in their actions. Due to their roles as cofactors, some micronutrients play important roles in the overall function of microorganisms or, more specifically, the enzymes created by microorganisms.
Beyond the essential macro- and micronutrients, there are additional elements that have been found to provide benefits to plant health. Although these elements are not considered essential, they provide specific benefits to cannabis plants and, therefore, should be considered important by cannabis growers. The three elements categorized as beneficial elements for cannabis are silicon, sodium, and cobalt.
Silicon (Si) — Of all the beneficial elements none are as important or widely used by cannabis growers as silicon. Silica formulations have become increasingly popular within the cannabis gardening community, as well as in commercial agriculture. Silicon’s popularity isn’t just marketing hype; horticulturists are flocking to silicon because the potential benefits are impressive. Silicon is associated with an increase in structural integrity, as well as heightened resistance to various pathogens. Silicon also helps cannabis plants negate stressful conditions, such as excess heat or drought.
Silicon is the second most abundant element in the Earth’s crust. The element can be found in many different forms. The most usable form of silicon by plants is silicic acid [Si(OH)4 or H4SiO4]. This form of silicon was once found naturally in the soil. Unfortunately, the amount of silicon within our soil is being depleted. Silicon has its own life cycle and can take hundreds of millions of years to naturally break down into a form that is usable by plants. The silicon cycle starts with active volcanos, which eject silicon-rich particles into the Earth’s atmosphere. The ash from the volcanos attaches to water droplets in the air and is then distributed onto the surface of the Earth. The freshly distributed silicic acid is then cycled into plants. Over many, many years, the silicon is washed to the bottom of the ocean into subduction faults. From there, the silicon is eventually distributed once again into the Earth’s atmosphere via a volcanic eruption. The cycle is then complete.
There are many different types of silicon products available to cannabis horticulturists. A product that is derived from silicic acid is generally a cannabis horticulturist’s best choice. For cannabis growers, silicon is one of those additives that can make a significant impact on yield and overall health.
Sodium (Na) — In certain plants, sodium aids in metabolism and the synthesis of chlorophyll. Some plants will use sodium as a substitute for potassium (for particular purposes, like aiding the opening and closing of stomata) when potassium levels are low. Adequate sodium levels are usually found in most media and fertilizers. Put another way, although important, sodium will rarely, if ever, need to be specifically supplemented.
Cobalt (Co) — Cobalt is an essential component of many enzymes and co-enzymes. This means cobalt has an indirect relationship with the beneficial microbes in the soil. Cobalt has been shown to affect the metabolism of plants in different degrees, depending on the concentration found in the soil or medium. Cobalt can also interact with other elements to form complexes. Cobalt’s absorption into the plant is dependent on the complexes formed.
Without access to trace minerals (specifically the essential micronutrients), a cannabis plant will never live up to its full genetic potential. A cannabis cultivator who provides his or her plants with the essential micronutrients, along with the beneficial elements, will give the plants what they need and supply the microorganisms with vital enzyme cofactors. This, in turn, creates the imperative catalysts for many of the chemical reactions happening in and around the root zone.
A cannabis cultivator who understands the important roles trace elements play (both direct and indirect) will be able to give his or her cannabis plants everything needed to be prolific flower producers.