80 to 90 days — 'Great Lakes 659' lettuce is tip-burn resistant, produces medium-large, solid heads, and does best in warmer weather. It is bolt resistant (very slow to go to seed), and does well in most parts of the United States. This 'Great Lakes' strain was bred and introduced by Dessert Seed Company, El Centro, California in 1944 and was developed as a selection made out of the USDA's original release of 'Great Lakes' lettuce.[1] Each packet contains one gram, which is approximately 500 to 600 seeds.