Giving our cannabis plants exactly what they need, down to the very last microbe in the soil, is a fundamental part of contemporary organic growing. Like any plant, cannabis has specific and highly complex requirements to grow optimally, and matching those requirements as accurately as possible allows our plants to achieve their full potential.
Conventional nutrient systems are relatively simple in their make-up, containing just the basic nutrients required for cannabis to survive and grow. There are six essential macronutrients (nitrogen, phosphorus, potassium, calcium, sulphur, and magnesium) and six essential micronutrients (manganese, boron, copper, zinc, molybdenum, and iron) that are present in most nutrient mixes for cannabis.
Conversely, organic nutrient systems often contain other trace elements that can provide extra benefits to cannabis, even if they are not traditionally classed as essential. Nickel, sodium, cobalt and chlorine are all examples of nutrients that have been demonstrated to be beneficial for higher plants such as cannabis, but are often overlooked in commercial feeds. Organic growers the world over report that organically-grown cannabis is superior in effect and potency due to the complex make-up of the nutrient mixes used.
Organically-grown cannabis is widely considered superior in flavour and aroma to conventionally-grown cannabis for similar reasons to those outlined above. As the micro-environment is optimised for vigorous, healthy growth, plants are able to produce optimum quantities of terpenes and terpenoids as well as cannabinoids themselves.
Cannabis plants collectively produce hundreds of biogenic volatile organic compounds (BVOCs). Terpenoids, sometimes referred to as isoprenoids, are the most diverse class of BVOCs. They are low weight hydrocarbons, mostly cyclic although acyclic forms also exist (e.g. myrcene), formed at least by carbon and hydrogen, but they may also present oxygen. Other BVOCs are benzenics, N- and S- containing compounds. According to the number of C5 units, terpenoids are defined as hemiterpenoids, monoterpenoids, and sesquiterpenoids, with 5, 10, and 15 carbon skeletons respectively. As the number of carbon units increases, their chemical diversity increases too. Thus, hemiterpenoids are mostly represented by isoprene and methyl butenol, around 1000 different structures have been reported for monoterpenoids, with limonene and a-pinene being the most common, and close to 5000 sesquiterpenoids have been detected in plants, the most universal being b-caryophyllene.
BVOC emission and storage allow plants to withstand numerous abiotic and biotic stress conditions and mediate ecological interactions with the biotic environment . Plants are not passive victims against herbivory since the important amounts of terpenoids specifically stored within plant tissues may act as antiherbivore chemical defences which make leaf consumption toxic for herbivores leading them to change their dietary habits and reducing the success of invading herbivores and pathogens. Complex mixtures of BVOC emissions also play an important role in the recruitment of the carnivorous natural enemies of herbivores . Leaf emissions of BVOCs, especially isoprene, protect the leaf cell against short episodes of heat stress . Terpenoids are highly reactive gases, and are emitted in such large quantities from the biosphere that substantially affect the oxidizing potential of the atmosphere and intervene in ozone (O3) and some aerosol formation.
Many study’s focused on the effect of inorganic and organic nitrogen fertilizers and their effects on yield and oil composition . They showed that when , nitrogen supply increased oil yield (mainly composed by terpenoid-like compounds) compared to plants fertilized with inorganic nitrogen alone. The mixture of inorganic and organic nitrogen also increased or decreased the concentration of different BVOCs contained within the essential oil
Nitrogen could promote terpenoid emissions by promoting electron transport rate and leaf photosynthesis which provide ATP requirements and carbon substrate availability for isoprene synthesis. Nitrogen is expected to favor terpenoid production, especially isoprene emissions, and mono- and sesquiterpenoid emissions. All carbon-based secondary metabolites ultimately depend on CO2 fixation and, as a result, a relationship between nitrogen and stored terpenoids can also occur. This is supported by previous work that reported a direct relationship between photosynthetic carbon products like glyceraldehyde-3-phosphate or pyruvate, and terpenoids biosynthesis as well as by studies were positive relationships between leaf or soil nitrogen and terpenoid concentration in leaves has been found.
Phosphorus is expected to influence terpenoid production since terpenoid precursors (IPP: isopentenyl diphosphate and DMAPP: Dimethylallyl pyrophosphate) contain high-energy phosphate bonds and phosphorus is a key component of ATP and NADPH which are required for terpenoid synthesis. Niinemets et al. (2002) estimated that 28 moles of NADPH and 40 moles of ATPis required to synthesize monoterpenoids. Phosphorus could hence be a key limiting nutrient involved in terpenoid emission and storage.
Isoprene emission could also be related to phosphorus availability since deprivation of this macronutrient degrades cell membranes, part of which seems to be compensated by greater isoprene emissions. In particular, phosphorus starvation reduces the amounts of phospholipids that form the bilayer in cell membranes, crucial for life in all organisms since it separates the interior of cells from their environment
Another aspect of organic cannabis cultivation that can enable improved, flavour and potency is the richness of the soil microbiome (“microbiome” refers to the community of microbes present in a particular environment). Organic soil mixes are complex living ecosystems in their own right, which contain an abundance of bacteria, fungi and other microscopic organisms such as nematode worms; the sterile environment found within many non-organic growing media does not support this level of complexity.
A substantial amount of research into cannabis and other important crops has demonstrated that establishing a rich soil microbiome has multiple benefits—it enables nitrogen fixing and water retention, stimulates growth and helps to prevent diseases of the roots. Making your own super-soil and leaving it to mature for around thirty days before use allows an abundance of fungi and other beneficial microorganisms to establish a niche and populate the soil.
Organic compost tea is another excellent way of culturing the beneficial bacteria required for a healthy microbiome. Compost tea involves steeping well-made compost in water and constantly running a bubbler to provide oxygen (allowing conditions inside the “brewer” to become anaerobic cause unhealthy bacteria to
develop instead of the beneficial types). Using either of these two crucial techniques allows Mr. Natural’s organic growers to develop a “food web” of beneficial organisms that will bring multiple benefits to the quality of the final harvest.