Nitrogen (N), phosphorus (P), and potassium (K) are the three major cannabis plant nutrients.
N-P-K (Wikipedia)
Many countries have standardized the labeling of fertilizers to indicate their contents of major nutrients. The most common labeling convention, the NPK or N-P-K label, shows the amounts of the chemical elements nitrogen, phosphorus, and potassium.
Nutrient Ratio, Fertilizer Ratio, Plant Nutrient Formula, Macronutrient Balance, Soil Nutrient Composition