Black Seeded Simpson is an 'heirloom' lettuce that was identified back in the mid-1800s. It is one of the quickest lettuce varieties to mature, taking between 45-60 days to complete its growing cycle. When grown in the right conditions, baby greens can be harvested in less than a month after germination. This lettuce is also known for its durability, withstanding heat and cold, as well as resisting infestations and other issues. Its light-green leaves are juicy and ideal for salads or other meals. When planting, put the lettuce 6" apart and 12" between rows.