Most gardeners know the frustration well. You plant a row of lettuce in spring, it looks gorgeous for a few weeks, and then, almost overnight, it shoots skyward, turns bitter, and the harvest is over.

Cut-and-come-again lettuce is one of the simplest and most productive crops you can grow at home. Whether in the ground, raised beds, pots, or indoors on a bright windowsill, you can get lots of tasty ...