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.
Baby-sized lettuce reaches maturity in about 4-6 weeks. Sow lettuce seeds every couple weeks to stretch out the harvest season. How to sow lettuce seed: Drop a small amount of lettuce seeds into one hand, then pinch the seed between your forefinger and thumb of the other hand. Drop the seeds thinly over the soil. Lettuce seeds are tiny, and they need light to germinate, so cover the seeds lightly -- never more than 1/4-in (.5 cm) -- with potting medium. Then, spray with water until thoroughly moist. Mist every morning to keep the medium moist at all times.