A unit of measurement used to describe the concentration of one substance within another. Specifically, it refers to one part of a substance per one million parts of the total solution or mixture. In cannabis cultivation and testing, PPM is commonly used to measure the concentration of nutrients in a plant’s water or soil, as well as to detect contaminants such as pesticides, heavy metals, or residual solvents.
In the Wild — Example
The nutrient solution was running at 800 parts per million which is ideal for mid-stage vegetative growth.
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