They never even consider winter crops. A mere dozen lettuce seeds, sown every 10 days from late winter through late summer, the earliest ones indoors for set-out later, will guarantee a small household plenty of fresh, succulent salad greens early spring through late fall. Don’t plant 10 feet of row of lettuce at a time—3 or 4 feet at most is more like it, since lettuce doesn’t keep. And even with those 12 seeds, I like to mix it up a bit, alternating 6 each of two varieties at each planting, so I have a blend of colors, tastes and textures in every bowlful.There are three basic categories of lettuces, the earliest being the looseleaf kind, which take only 45-60 days to mature. ‘Black-Seeded Simpson,’ at 45 days, is about the quickest of all, so don’t be without it. Another non-heading lettuce I always grow is ‘Oakleaf,’ with beautiful ruffled leaves shaped like its namesake’s. There are red forms now, like ‘Flame,’ or various improved v