Cal-mag, a widely used supplement in the realm of plant cultivation, is often hailed for providing essential calcium and magnesium to support overall plant health. While it’s not a Plant Growth Regulator (PGR) in the traditional sense, some growers speculate on its potential to enhance flowering, particularly in cannabis cultivation. This belief, however, lacks substantial backing from scientific research and may be rooted more in anecdotal reports and personal preferences than concrete evidence.

Despite claims by certain growers marketing cal-mag as a PGR, it is crucial to dispel the misconception. Cal-mag, by design, does not directly influence critical physiological processes such as cell division, elongation, or flowering. The misguided promotion of cal-mag as a PGR can mislead customers, fostering expectations that may not align with the supplement’s actual capabilities.

Organic growers employing super soil, a nutrient-rich planting medium, further complicate the narrative. Super soil formulations, enriched with various organic components, aim to provide a comprehensive nutrient profile throughout the plant’s entire life cycle². Ingredients like bat guano, kelp meal, and dolomite lime contribute to a well-balanced nutrient environment, potentially rendering the addition of cal-mag redundant or even counterproductive.

Creating super soil involves a meticulous blend of base soil, perlite, earthworm humus, and an array of organic amendments. Depending on the recipe, super soil may already contain sufficient calcium and magnesium, making additional cal-mag unnecessary. In fact, excessive use of cal-mag in conjunction with super soil can lead to nutrient lockout, pH imbalances, and salt buildup⁸, adversely impacting plant growth and overall health.

Adding to the Discussion: Unraveling the PGR Predicament

In the broader landscape of cannabis cultivation, a dark shadow looms—Plant Growth Regulators (PGRs). Some cultivators, driven by the pursuit of higher yields, resort to these artificial hormones that alter a plant’s development. PGRs, including paclobutrazol, daminozide, and chlormequat chloride, have raised concerns about potential long-term health effects, particularly with paclobutrazol interfering in natural cell growth.

Amidst these concerns, a ray of hope emerges with the exploration of more natural, non-toxic PGR alternatives such as kelp, chitosan, and triacontanol. Additionally, plant growth-promoting rhizobacteria (PGPR) are being investigated as safer alternatives, offering benefits like increased nutrient absorption and mold resistance. As the debate over PGRs unfolds, it becomes evident that sustainable and natural alternatives pave the way for responsible cannabis cultivation, ensuring both yield and product safety.

Plant growth-promoting rhizobacteria (PGPR) are beneficial bacteria that colonize the rhizosphere (root zone) of plants, promoting plant growth and health. Here are some examples of PGPR:

1. Azospirillum: This genus of bacteria is known for its ability to fix nitrogen and enhance nutrient uptake in plants.
2. Bacillus subtilis: A common soil bacterium that produces substances promoting plant growth and providing protection against pathogens.
3. Pseudomonas fluorescens: Known for its ability to suppress soil-borne pathogens and promote plant growth by various mechanisms.
4. Rhizobium: These bacteria form symbiotic relationships with leguminous plants, aiding in nitrogen fixation.
5. Enterobacter spp.: Some strains of Enterobacter have been identified as PGPR, contributing to plant growth promotion.
6. Streptomyces: Although primarily known for their role in producing antibiotics, some Streptomyces strains also exhibit plant growth-promoting properties.
7. Bacillus megaterium: This bacterium is known for its ability to enhance nutrient availability and protect plants from diseases.
8. Paenibacillus polymyxa: Exhibits plant growth-promoting activities and can contribute to biocontrol against plant pathogens.
9. Burkholderia spp.: Some strains of Burkholderia have been found to have beneficial effects on plant growth.
10. Serratia spp.: Certain Serratia strains can act as PGPR, promoting plant growth and suppressing pathogens.

It’s important to note that the effectiveness of PGPR can vary depending on environmental conditions, plant species, and specific bacterial strains. As research in this field continues, more strains of bacteria with plant growth-promoting capabilities may be discovered.

The impact of Plant Growth Regulators (PGRs) extends beyond altered growth patterns in plants. There is evidence suggesting that PGRs can induce adverse mutations and even trigger seed dormancy in seed-producing plants. This adds another layer of concern, emphasizing the potential long-term effects and risks associated with the use of synthetic growth regulators in agricultural practices. As the understanding of these substances evolves, it becomes increasingly important for growers to consider not only immediate effects but also the potential repercussions on the reproductive capabilities and genetic stability of plants.