When buying lettuce, the leaves should be crisp and hold their shape, with no slimy spots or blemishes. Frisee has a looser head and not as crisp as butter crisp lettuce. Romaine and radicchio should stand up straight without cracks along the ribs. Lettuce likes soil with compost that includes rock powder and oyster shells. Lettuce is still alive and lets off carbon dioxide. It still has dirt on it. Put it in a sink full of water and the dirt will fall to the bottom. Cutting lettuce breaches cells and you get bruised edges. Tearing goes along the cells edge. Washed lettuce stays crisp in the refrigerator. You should dry the lettuce afterwards with a salad spinner. Store them wrapped in a paper towel put inside a paper bag with the air sucked out. The average American eats 30 lbs. of lettuce a year.