NPK refers to the three primary macronutrients in any fertiliser or nutrient solution: Nitrogen (N), Phosphorus (P), and Potassium (K). The NPK ratio printed on nutrient bottles (e.g., 3-1-2) indicates the percentage by weight of each element. Nitrogen drives leafy vegetative growth, phosphorus supports root development and flowering, and potassium regulates water uptake, disease resistance, and overall plant vigour.
Key Facts
- N (Nitrogen): essential for chlorophyll, proteins, and vegetative leaf growth
- P (Phosphorus): drives root development, flowering, and energy transfer (ATP)
- K (Potassium): regulates stomata, water uptake, enzyme activation, and disease resistance
- Ratio 3-1-2 is a common vegetative baseline; flowering stages often shift to lower N, higher P/K
- Deficiency symptoms are element-specific: yellow older leaves (N), purple tints (P), brown leaf edges (K)
- Hydroponic nutrient solutions must supply all three in precise ratios β soil buffers these naturally