Plant Growth Regulators. PGR refers to a group of chemicals that gained popularity in the cannabis growing industry due to their ability to make for healthier plants with much denser buds. However, they quickly became just as unpopular
whenit was discovered that PGRs are linked to cancer and infertility. PGRs are illegal in many places now, but if you somehow get your hands on something with synthetic PGRs, please don’t use it!