- You will get 450 Seeds of Tom Thumb Leaf Lettuce Heirloom Garfden Vegetable Seeds. - Sunlight: Full Sun. - Life Cycle: Annual. - Watering: Medium. - Tom Thumb Butterhead Leaf Lettuce seeds!. - This heirloom is the oldest American lettuce still in cultivation, dating back to 1830, which speaks to its charms. Plant Tom Thumb lettuce seeds for the smallest of the dwarf lettuces– a baseball sized bibb lettuce. Light, creamy yellow centers with green, slightly crumpled wrapper leaves. Perfect for indoor gardens and container gardening. - Germination: Work and prepare soil bed while average daily highs are still in the lower 70's. Barely cover seeds with a thin layer of soil and water frequently until seedlings emerge, about 10 days. Thin to 4 inches apart. Lettuce thrives in cold weather and can be sown directly into the garden, starting in early spring. For an even earlier harvest, sow indoors; the seedlings don't mind transplanting. 600 seeds will sow a 30-foot row.