I learned this from a produce guy at the grocery store. In Wisconsin in winter, our lettuce from California can use a little sprucing up. I slice off the bottom (1/2" maybe?) of the lettuce head and put it in a bowl with water just to cover the bottom, cover with a plastic bag and refrigerate. One day later, the lettuce head is considerably larger and the leaves are crispy! Can you tell which is which from these pictures?