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.
How Lettuce is Grown and Harvested. Weâre a rounded mass of leaves growing from short, central stems,either in soil or hydroponically (in water). Weâre harvested, when immature, by cutting the stem below our leaf mass. Today, weâre generally grown hydroponically in a nutrient solution.