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.
3. Trim back the entire plant when it reaches 3 to 6 inches high, or approximately every 10 days. Cut back to within 1 to 2 inches of the ground. Most loose-leaf lettuce varieties grow back from a severe trim to produce more leaves.
âThe leaves make perfect boats for lettuce wraps, which benefit from the crispiness that iceberg lettuce is known for.â. To clean iceberg lettuce, give the head a good rinse under cool running water and pat dry. Place on a cutting board and remove outer leaves that may be dirty or wilted, usually just the outer four.