Harvesting and Storing Lettuce
To keep lettuce plants growing and growing, the best way to cut the leaves is from the outside of the plant in. Cut the outside leaves about 1 inch above the crown, leaving a smaller set of leaves in the center. This is often called the "Cut and Come Again" method of harvesting lettuce and is ideal for leaf lettuce varieties. Take what you need and use the same procedure the next time.
I like growing loose leaf lettuce because it allows me to use just what I need along the way rather than having too many heads of lettuce ready to eat at once.
To keep cut lettuce fresh, first wash the leaves thoroughly and dry them as much as possible using a salad spinner (my preferred method) or pat dry with paper towels. (As you can see from the photo, my lettuce leaves love picking up the dirt.) Place a bunch of leaves along with a few small pieces of paper towels in a gallon zipper bag and close the bag, leaving about 1-2 inches open. I find the lettuce stays fresh and crisp for a week or so using this method.