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Iron Deficiency

Iron Deficiency

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A cannabis iron deficiency is characterized by the appearance of bright yellow new leaves, which can sometimes coincide with other nutrient problems or deficiencies in cannabis plants. This deficiency is often caused by issues with pH levels, particularly when the pH at the roots is too high. However, it can also be triggered by environmental stress, with the symptoms resolving on their own after the stressful period ends. The yellowing of new leaves, especially their bright yellow or almost white coloration, is the prominent sign of an iron deficiency. In some cases, the affected yellow parts of the leaves may gradually turn green as the plant continues to grow, starting from the tips and moving towards the base. It's worth noting that while an entire yellow leaf can eventually regain a green and healthy appearance, this ability is unique to iron deficiencies compared to most other nutrient deficiencies. Although a cannabis iron deficiency may resemble a magnesium deficiency, it primarily affects newer, upper, and inner leaves, while magnesium deficiency tends to impact older and lower leaves.

Cause of Issue
◉ An iron deficiency in cannabis plants can be caused by problems with pH, particularly when the pH at the roots is too high. ◉ The use of certain fertilizers, such as chicken manure, can raise the pH of the soil, leading to iron deficiency. ◉ Nutrient lock-out conditions can occur when high levels of nutrients, like those found in chicken manure, interfere with iron uptake by the roots.
Symptoms
◉ Newest leaves are completely yellow when they first grow in, with a bright yellow, almost white appearance. ◉ Affected yellow leaves may begin to turn green as the plant continues to grow, starting from the tips and moving towards the base of each leaf. ◉ In some cases, an entire leaf can become green and relatively healthy-looking, even though it started out completely yellow. ◉ A cannabis iron deficiency can resemble a magnesium deficiency, but it primarily affects newer/upper/inner leaves, while magnesium deficiency affects older/lower leaves.
Corrective Actions
◉ Adjust pH to Correct Range: Ensure the pH at the roots is within the proper range. In soil, iron is best absorbed in the 6.0-6.5 pH range, while in coco coir or hydro, the range is 5.5-6.5 pH. If the pH is too high, flush the system with clean, pH-adjusted water to remove nutrient salts that may affect iron uptake and restore pH levels. ◉ Give the Right Nutrients: Most cannabis growers don't need to add more iron, as it is usually present in tap water and cannabis-friendly nutrients. Iron deficiency symptoms caused by a true lack of iron are more likely to appear when using heavily filtered or reverse osmosis (RO) water. Ensure a balanced nutrient regimen, addressing other nutrient problems that can trigger iron deficiency symptoms. ◉ Take Good Care of the Roots: Ensure proper watering practices to avoid overwatering or root problems, which can contribute to iron deficiencies. ◉ Watch for Recovery: After implementing the above steps, monitor the plant for signs of improvement within a week or so. New growth should start coming in green, indicating that the iron deficiency is clearing up.
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