Quote Originally Posted by JCO
Are the leaves of the lettuce close to the cold frame wall or plastic or glass(whatever lets the light in) If so, it could be burn from the sun as glass would magnify the intensity of the sun even though it didn't get any higher than 75 or it could be caused by cold at night if it has gotten that low there or you are like Jackalope and just don't have any luck with lettuce

thanks for the info..i'll look into it. for now i am opening my cold frame during the day. failing at this is not option: if i don't have salad on the table soon, my wife cuts the funding...and the fun is over