Sowing: Lettuce grows well in cool weather, so the first crop can be direct sown when the soil temperature reaches at least 35 degrees F, or as soon as the soil can be worked. Direct sow heirloom romaine lettuce seeds in rich soil and full sun, spreading them as thinly as possible in rows 1-2' apart; when the seedlings begin to grow, thin them to a distance of 10-12".
eBay