|'Sugar' Lettuce, also known as 'Swede', is a white-seeded heirloom variety which dates back to the 17th century. It has large, floppy leaves with ruffles edges tinged pink, and heads 12 inches in diameter. The back sides of the leaves have small spines on the ribs. Start from seed 4 to 6 weeks before average last frost date. Sow seeds 1/4 inch deep in wide rows and thin to 8 to 12 inches apart. Thinned seedlings can be replanted. Keep soil moist but not soggy. Protect from rabbits and slugs. Extend the harvest season by planting successive crops. Summer heat causes lettuce to bolt. Pick outer leaves as they grow or harvest all at once. Harvesting when weather or day temperature is cooler will result in crisper leaves. Do not harvest lettuces until you are ready to use it.