This is the first year we're growing lettuce in the garden. I'm not as familiar with lettuce heads, but loose greens, like a salad mix, grow quickly, easily, usually produce 2 good crops per plant, and can be direct seeded into the garden in cycles, every 2-3 weeks if you have the space.
Sadly, Chris isn't a fan of lettuce or, for that matter, any raw greens. But he agreed to eat greens grown in the garden (or from a CSA), so tough luck for him. For the future, I need to find an entire seed pack of the lettuce we had last year in our CSA (butterhead, or oak leaf buttercrunch, or whatever it was). It was the best, softest and sweetest lettuce we'd ever tasted.