To define a number range, you have to create a new number interval: 1  Specify an alphanumeric key with up to 2 characters. 2  Specify the limits of the number interval.  Mark the number range if it is planned for external number assignment.
Inspect the lettuce plants for leaves that are ready to harvest. Most leaves are mature enough once they reach 1 to 3 inches long, but they should still be tender up to 6 inches long. Cut off the outer leaves of the plants with a small pair of garden shears to harvest just a few leaves.
Step 3. Photo Credit Stephanie Loaiza/Demand Media. Remove the separate lettuce leaves by hand, if desired, and pat each dry with paper towels or use a salad spinner to free the leaves of as much water as possible. Use paper towels to pat dry the outside of the head of lettuce if you plan on storing it whole.