On average, a head of lettuce weighs about 800 grams. Each leaf on a head of lettuce weighs between 6 and 12 ounces. The length and width of each lettuce leaf ranges from 2 to 3 centimeters.
Lettuce is a significant source of vitamins A, C and K as well as folate and iron. Lettuce also has a high water content along with carbohydrates and dietary fiber. Butterhead lettuce is planted during the spring. The seeds need plenty of water and should be 1/4 to 1/2 inch into the ground. Romaine lettuce can be started indoors. The seeds need well-drained, rich soil to thrive.