mmm…. I`ve never had that with new leeks, only with mature, over wintered plants which is normal as they reach the end of their life. It could be the sowing date, I am tending to sow earlier than I used to but not until the beginning of April. I think its more likely to be weather related, most of my leeks this year have developed long pale stems and I was wondering if they were going to bolt.
Pete:-)