Cal-Mag is a liquid hydroponic supplement combining Calcium (Ca) and Magnesium (Mg), two secondary macronutrients that are frequently deficient when growing in soft water, coco coir, or with certain base nutrient formulas. Calcium strengthens cell walls and prevents tip burn; magnesium is the central element in chlorophyll and is essential for photosynthesis. Cal-Mag is added to the nutrient solution in addition to standard base nutrients.
Key Facts
- Soft water and RO (reverse osmosis) water lack baseline Ca and Mg β Cal-Mag compensates
- Coco coir actively binds calcium ions, making additional supplementation essential
- Calcium deficiency: brown leaf edges, tip burn, blossom end rot in fruiting crops
- Magnesium deficiency: interveinal chlorosis (yellowing between veins) on older leaves
- Typical dose: 2β5 mL per litre depending on water hardness and base nutrient formula
- Add Cal-Mag to water before base nutrients to prevent precipitation