Maximum Yield USA 2014 March | Page 58

Why are my leaves turning yellow? Magnesium Deficiency By far the most common nutrient deficiency in hydroponics is magnesium deficiency. Magnesium is a mobile element, which means if a magnesium deficiency starts to develop, the plant can pull the magnesium out of the lower leaves and transport it to the top leaves where it is needed the most. Since magnesium is the central element in chlorophyll, the bottom leaves develop interveinal chlorosis—the veins would remain green, but the tissue between the veins would begin to turn yellow. Plants need plenty of magnesium when their energy requirements are highest, and sometimes during times of rapid vegetative growth or heavy fruit production, plants can’t keep up with demand for magnesium. In this case, adding a little cal-mag to the reservoir, or spraying a little magnesium sulfate on the leaves will green up the plants in a hurry. 56 Maximum Yield USA  |  February 2014 March 2014 Plants need plenty of magnesium when their energy requirements are highest, and sometimes during times of rapid vegetative growth or heavy fruit production, plants can’t keep up with demand for magnesium.” Magnesium is a mobile element, which means if a magnesium deficiency starts to develop, the plant can pull the magnesium out of the lower leaves and transport it to the top leaves where it is needed the most.