Romaine lettuce is characterized by its tall head and dense, ridged leaves, which are often used in salads like Caesar, as well as other Mediterranean and Middle Eastern dishes that require a crunchy, faintly sugary taste. This type of lettuce is thought to be particularly nutritious, containing vitamins A, B and C and a wide selection of minerals. Romaines are somewhat more tolerant of high temperatures than other lettuces and usually become mature within 70 to 80 days. The recommended spacing between plants is 8 to 10 inches, with 12 to 16 inches in between rows.