Add to cart Cal-Mag R90.00 Comes in 1kg packets Ingredients: Calcium nitrate, magnesium nitrate 2-1 Ratio Feeding Schedule: 1/4tsp per 3 Litres of water Cal-Mag (Calcium – Magnesium) As the name suggests, Cal-Mag contains calcium and magnesium, along with nitrogen, phosphorus and potassium, so be careful when considering this control method. Do not use Cal-Mag during the flowering stage or the flowers will receive too much nitrogen. This treatment should be applied during the vegetative stage. Cannabis roots absorb calcium and magnesium in a proper pH level (6.5). If the pH is off, calcium deficiency can result in the forming of dead spots in the leaves, then crinkling or spotting. Follow instructions and don’t over-apply or you can end up raising the essential nutrient levels too high.