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.
For maximum lettuce production, it's wise to select a site where the soil drains well, yet retains some moisture. The soil should also be rich in nitrogen and potassium, The best way to accomplish this is to work in plenty of organic matter (compost, rotted manure, or leaf mold) that will loosen and enrich the soil.