Macronutrients are the mineral elements that plants require in large quantities for healthy growth. There are six primary macronutrients: Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca), Magnesium (Mg), and Sulphur (S). In soil-based growing, these are partially replenished by organic matter decomposition. In hydroponics, they must all be supplied in precisely calibrated concentrations through the nutrient solution.
Key Facts
- Primary macros: N, P, K β needed in the highest quantities
- Secondary macros: Ca, Mg, S β needed in significant but smaller amounts
- Calcium strengthens cell walls; deficiency causes tip burn and blossom end rot
- Magnesium is the central atom in chlorophyll; deficiency causes interveinal yellowing
- Sulphur is needed for amino acid synthesis; deficiency causes pale new growth
- All six must be present in balanced ratios β excess of one can block uptake of another