My plants are turning a bit yellow. I wanted to add some chelated iron. Could not find any in the stores. All I found was this:
Would this be safe to use in an aquaponic system?
if the leaves are pale you need a little more nitrogen meaning a few more fish probably or foilar feed leaves with fish emulsion without getting it in the system , if they are yellow and green streaked it is iron def
steven baxter said:
So I bought some chelated iron on-line it should come soon. My plants are fine and growing fast, but still a little on the pale side. Thanks for the help. Ill let you know how it turns out after a dose of iron.
If the older leaves are yellowing and the nitrate readings say 0 then it might be nitrogen deficiency or too few fish.
However, if newer leaves are yellowing while the veins stay green then it's Iron Deficiency. If old leaves are yellowing while the veins stay green then it is another deficiency.
Not all yellowing is nitrogen deficiency.