'Tom Thumb' lettuce is a unique, mini butterhead lettuce, producing heads about the size of a baseball. Perfect for individual salads, container gardens, and for those who don't have a lot of garden space. 'Tom Thumb' lettuce has a deliciously fresh, crisp flavor, and is much slower to bolt than larger varieties. 1/2 g. seed packet Name: Lettuce ‘Tom Thumb’ Botanical Name: Lactuca sativa Days to Maturity: 30-40 When to sow outside: 2 to 4 weeks before average last frost. Successive Sowings: Every 3 weeks until 2 weeks before the first fall frost. Harvesting: Harvest mature plants by cutting off at ground level. If regrowth is desired, cut the leaves higher, at 2″. For a continual supply, outer individual leaves can be harvested at any time, but leave at least half of the plant for regrowth.