|'White Seeded Simpson', also known as 'Silesia', 'Early Curled Silesia', and 'Curled German Batavian' is an heirloom variety. It is extremely hardy and can be grown in cold-frames or under straw coverings. Hard freezes won't generally kill it. This plant forms a tight bunch of crumpled, light green leaves 12 to 14 inches across. It is quick growing. 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.