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Plant Growth Regulators


For those in the cannabis scene, growers, extractors, consumers or budtenders, the acronym PGR is far from foreign. Plant Growth Regulators are utilized to boost hormones in plants called phytohormones. Just like the hormones in our bodies, hormones in plants can have dramatic effects on both the physical appearance and the chemical makeup of a crop. Researchers have identified five key hormones that affect density, overall structure, resilience to pest and molds, and terpene profiles. Hormones play a huge role in the development and growth for cannabis plants, leading many to take a non-organic approach to artificially bolster a crucial aspect of what, on face-value, we call “healthy” plants.

Can PGRs increase yields? 

Plant Growth Regulators have been shown to increase yield and uniformity over a crop. PGRs create (essentially) swollen plant cells via two differing ways. First off, the presence of PGRs lead to increased water retention in cytoplasmic-cells within the central vacuole. Resulting in greater than normal amounts of water within individual cells,  the subsequent added pressure that this causes translates into expansion of cellular-walls. The second way PGRs produce swollen, “fat nugs”, is through Acid Growth Hypothesis. By providing auxins, which de-neutralize the pH within the cellular walls, the subsequent acid tends to expand plant matter via facilitation from specific proteins. As the cell wall expands it becomes filled with celluloses which results in additional, and artificial plant weight.

Are PGRs dangerous? 

Well...the jury is still out. PGRs are banned from edible foods and have been for nearly 5 decades. In many countries these chemicals are held to the same standards of harm as pesticides. Daminozid was the notorious PGR responsible for the “Alar Scare” that led to $100 million in losses for US apple farmers after it was barred due to being found to be carcinogenic to humans.  While concrete scientific answers have not been published regarding the negative health effects PGR in cannabis can result in, a cautionary tale is far better than the blind approach many growers currently take. With that being said I think consumers should be more than accepting with regards to cannabis that is completely free of questionably harmful growth regulators. 

PGRs are often used in the cannabis industry for both increased yields and improved bag appeal. These chemicals have directly led many strains to the hype that they have notoriously garnished. More times than not, your praised, overly-dense and trichome glistening nugs become reality through the use of nutrient lines containing some form of a PGR. Taking questionable short-cuts, PGRs inorganically force desirable characteristics, tricking and potentially harming clueless consumers. This is not to say that people cannot grow good cannabis without PGRs. However, often these crops sadly lack the mainstream flare many consumers look and demand for. Creating uniformly successful grows, all while theoretically increasing profit margins, it is not impossible to see why this hidden trick is used so often. But it does make me wonder; have we as consumers pushed the cannabis industry towards using plant growth regulators based on high expectations? Or has the supply chain become far too unconfident to risk a grow without this chemical-boost.

- Evan

Host of the Maine Potcast

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