This type of lettuce does not form a tight head and is grown for its soft, fragile leaves that sprout from a central stem. They reach their peak between 45 to 55 days after germination, though larger leaves can be picked any time during its growth cycle. Like other lettuce, looseleaf types are delicate to too much sunlight and heat, which could lead to them bolting and wilting. It is often used in salads and sandwiches. When planting, space each seedling 6 inches apart, leaving 12 inches between rows.