Great Lakes Lettuce Seeds (Crisphead Type) 1780 Heirloom Vegetable. This crisphead variety has nicely formed heads that are large and solid. A vigorous, disease resistant variety that withstands hot, dry weather better than any other variety. Introduced in the early 1940’s. How to Grow 880 seed/gram. Lettuce is a sun-loving cool weather crop that grows best in organic, well drained soil. Sow as soon as the soil can be worked in the spring, then every two weeks thereafter to ensure a continuous supply. Sow about 3 mm (1/8″) deep in rows 45 cm (18″) apart. An even supply of moisture during the entire growth period is imperative for success. Gradually thin seedlings to 30 cm (12″) apart. Harvest head lettuce by cutting the head off at the base just below the lower leaves. Once lettuce bolts (starts to produce a rapidly growing flower stem) leaves become bitter.
