Molybdenum
may appear similar to a nitrogen deficiency (yellowing of older, lower leaves). Leaves may become mottled or spotted. However, the tell-tale sign of a molybdenum deficiency is the leaves may start to display a unique orange, red or pink color around the edges which will start to move toward the center of the leaf. Sometimes the color appears in the middle of the leaves as opposed to the edges.
A real molybdenum deficiency in cannabis is rare, and even scientists didnt really know this mineral that is needed by most plants because it's often present.
For cannabis plants, molybdenum tends gets locked out at lower pH ranges. Your plant may show signs of a molybdenum deficiency if the pH at the roots is too low, although it's likely that molybdenum is there. and That is because when the pH of your root zone is off, your plant cannot properly absorb molybdenum through its roots.
Therefore the first step is to ensure that you have the correct pH for your growth medium.
