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Magnesium Deficiency

Magnesium Deficiency

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A cannabis magnesium deficiency is characterized by the appearance of light green or yellow coloring on the veins and edges of lower and older leaves. This discoloration is often accompanied by red stems. Magnesium, being a mobile nutrient, can be transferred from older leaves to newer ones within the plant. Therefore, a deficiency typically manifests in the lower parts of the plant and affects older, less vital leaves. The affected leaves may exhibit yellowing or bright green coloration, with a crispy texture along the edges. It's important to note that this crispiness is distinct from nutrient burn, as it doesn't extend into the inner leaf areas. In some cases, red stems may also be observed, although this isn't always present. As the deficiency worsens, light brown spotting might appear within the margins or along the leaf edges, although this can also be indicative of other deficiencies that often occur alongside magnesium deficiency.

Cause of Issue
◉ Supplementation with calcium sources lacking magnesium ◉ Improper pH in the root zone, especially in hydroponic setups
Symptoms
◉ Light green or yellow coloring between the veins on older leaves ◉ Red stems (sometimes) ◉ Crispy texture along the edges of affected leaves ◉ Possible light brown spotting within margins or along the edges (in severe cases)
Corrective Actions
◉ Ensure the pH of the root zone is within the optimal range (6.0-7.0 for soil, 6.0-6.5 for hydroponics). Maintaining proper pH is crucial for magnesium absorption. ◉ In hydroponic or coco coir setups, supplementing with extra calcium and magnesium is often necessary, along with regular nutrients. ◉ Flushing the system with pH-adjusted water containing cannabis-friendly nutrients that include magnesium can help remove nutrient salts and restore pH levels. ◉ Use Cal-Mag (calcium-magnesium) supplements, which are beneficial for hydroponic, coco coir, or soil cultivation. ◉ Consider using organic dolomite lime to supplement magnesium in soil setups. Dolomite lime gradually releases calcium and magnesium over time and can help buffer pH. ◉ Regularly check and adjust the pH and nutrient levels in the growing medium or hydroponic reservoir to ensure proper nutrient uptake. ◉ When using filtered or reverse osmosis (RO) water, supplementing with Cal-Mag is essential since these water sources may lack necessary nutrients like magnesium, calcium, and iron. ◉ It's important to note that once a magnesium deficiency is resolved, the yellowing of lower leaves should cease spreading to other older leaves within a few days. However, damaged leaves affected by the deficiency may not fully recover or regain their green coloration. Monitoring new growth for signs of recovery is essential, and any further discoloration should be observed primarily in already affected leaves before considering their removal.
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