Got home from a family emergency in Florida (I live in NW IL). I'd been planning to plant a bed of spinach and then one of lettuce in late spring (the rule is, here, to plant non-frost-resistant vegs after Mothers' Day but spinach and some greens seem frost tolerant). When I got called to come take care of my parents for a few weeks, I just tossed the seeds into my "greens" bed. Came home to a half-dozen heads of romaine lettuce! I was tickled pink. They're slightly bitter. My husband and I rather like some bitter in our greens, but what causes it?
