A plant needs magnesium for photosynthesis, production of key enzymes and other important functions. The amount needed can vary by strain, medium and lightsource used.
Magnesium is an important secondary nutrient that marijuana plants need for healthy growth. Like nitrogen, phosphorus, potassium, calcium and sulfur, it belongs to the group of macronutrients. Macronutrients are nutrients that your plants need in large quantities. Your plants need it, but less in quantity compared to the three primary macronutrients: nitrogen (N), phosphorus (P) and potassium (K). Like the primary nutrients, secondary nutrients are essential.
Magnesium is also a mobile nutrient. That means the plant can move it from older leaves to new leaves. This is why you can usually first recognize a magnesium deficiency in the older, lower leaves, rather than in new growth.
Magnesium is mainly present in the leaves because it is an essential component of the chlorophyll molecule. Its presence or absence therefore directly affects the plant's ability to absorb light and then produce sugars and carbohydrates. Low magnesium levels result in your cannabis plant struggling to grow. In addition, magnesium also aids in the production of enzymes.
- Magnesium plays an important role in converting light into energy.
- Regulates enzyme production.
The time just before your plants start flowering is when the plant grows most vigorously. In doing so, some cannabis strains grow as much as two or even three times their size within a week. To support this vigorous growth, the plant needs nitrogen and extra amounts of magnesium and calcium. Magnesium is essential for plants to convert light into energy. Therefore, a magnesium deficiency negatively affects plants and yields.
Magnesium is a mobile nutrient. This means that signs of a deficiency appear first at old growth. Symptoms of a magnesium deficiency are:
- Leaf margins turn brown or yellow, especially of older leaves
- Yellowing at the leaf veins and edges
- Red or purple stems
- Brown spots or patches
Symptoms of excess magnesium:
- Leaves turn dark brown or black
- Leaves point upward
- Symptoms of calcium blockage due to excess magnesium.
It is difficult to correctly determine a magnesium deficiency or surplus. This is because nutritional deficiencies and excess cause similar symptoms.
For optimal uptake, a good ph of your medium and the amount of calcium in relation to magnesium is needed.
Kieserite Magnesium 20 gr / 0.7 oz per m2 / 10.8 sqft
Seaweed Calcium 100 gr / 3.53 oz per m2 / 10.8 sqft