Hi everyone, planted some "Hercules" onions a while ago, after starting them off in the greenhouse. They are in a composted raised bed. They are growing on just fine, but some of the leaf tips are yellowing. Not sure what may be wrong. previously I have grown "over winter" onions, so this is my first go at spring planted. Any suggestions please? I am going to let em carry one and see what happens. Photo hopefully attached.