Sometimes we find ourselves with pods of varying ages in our gardens.  Maybe one didn't germinate, or we pruned too aggressively, or maybe the cat took a nap in the chives!  Whatever the reason, its really important to catch the new plants up to the old if you want a good looking and productive garden.  To do this, be sure to keep the lights down low and prune back the bigger plants to keep them from shading the young ones.  If you start raising the lights or letting the bigger plants shade the young ones, your youngsters will never really amount to much.  They need light to catch up -- so keep the lights low and prune aggressively.