Three Spring and Fall plantings in diffterent areas. The only thing in common was the seed. But I can't rule out a soil condition...I just don't know what. All the other cold crops that produce heads (brussel sprouts and cabbage) did fine. The lettace started getting purple fringes on the leaves while still small. I read somewhere this is a sign it will bolt - but they said blue, not purple (maybe their color vision was off) but didn't specify a cause except heat. Heat has not been a problem on two of my plantings. I thinned them in a timely manner but they bolted anyway. Any ideas?
BTW - the variety is iceburg from Bunton Seeds.