Can someone help me ? I started tomatoes from seed on Jan. 8, repotted them on Feb 5 into styrofoam cups with MG organic potting mix and all plants are growing and doing well, almost. I have them under a grow light for about 12-14 hours per day. On some of the tomatoes the lower leaves are turning yellow and dying. The top leaves look fine and they continue to sprout new growth. Do I have a major problem with the plants who's leaves are dying and falling off? I want to plant them in the garden this weekend. Thanks!