I have been eating a ton of salad lately. I love it. Romaine is really my lettuce of choice. So obviously when I saw that you could re-grow lettuce from the ends, I had to try it.
Usually, after I'm done cutting up lettuce at my house (which, is rare to begin with), I just toss of the stump of the head or toss it outside for the animals.
But next time you have that stump in your hand, maybe you will want to try this instead of just tossing it out.