Yellow patches on leaves
Growing tomatoes in an NFT system and though they seem to be growing well, the lower leaves are developing yellow patches but the veins remain dark green. This seems to be working its way up the plants too, so higher leaves are now showing signs of it.
I have read this could be a mag deficiency but adding some doesnt seem to be sorting the problem.
As the plants look quite good and are growing (apart from this leaf problem) should I just leave it alone? I;m stuck as to what to do.