perilite n - sand or volcanic glass, expanded by heat, used as a planting medium
pesticide n - a chemical used to kill pests (as rodents or insects)
pH n - a measure of the acidity or alkalinity of a substrate or solution, numerically equal to 7 for neutral, increasing with increasing alkalinity and decreasing with increasing acidity. The pH scale commonly in use ranges from 0 to 14
phosphorus (P) n - a multivalent nonmetallic element of the nitrogen family that occurs commonly in inorganic phosphate rocks and as organic phosphates in all living cells; one of three major nutrients used by the cannabis plant as a primary component in the synthesis of molecular complexes such as genes, and is necessary to the development of energy transfer compounds, which are required for photosynthesis and respiration
photoperiod n - The duration of a plants daily exposure to light and darkness, considered especially with regard to the effect of the exposure on growth and development
photosynthesis n - the process in green plants by which carbohydrates are synthesized from carbon dioxide and water vapor using light as an energy source, releasing oxygen as a byproduct;
pistil n - The female, ovule-bearing organ of a flower, including the stigma, style, and ovary
pollen n - The fine, powder like material consisting of pollen grains that is produced by the anthers of seed plants; fine grains contain male gametes
pollinate v - To transfer pollen from an anther to the stigma of (a flower).
potassium (K) n - a light soft silver-white metallic element of the alkali metal group; one of three essential plant nutrients used by the cannabis plant for certain plant processes, such as photosynthesis, respiration, and uptake of nutrients to occur, which has been linked to a healthy infrastructure, growth, and resistance to disease
potency n - capacity to produce strong physiological or chemical effects
ppm - acronym for Parts Per Million; measurement used to determine the amount of dissolved chemicals in a solution as in nutrients in water
propagate v - to cause to continue or multiply by generation, or successive production
pruning v - to cut off or remove dead or living parts or branches of a plant to improve shape or growth; trimming a plant | 
