Big Boy tomato in earthtainer is turning yellow. About 2 weeks ago I noticed my 6 ft plant started turning yellow. Before this it was a pretty dark green healthy plant with no problems. The whole plant started losing it's dark green color and slowly turned lighter green and now some of the leaves are turning yellow and dieing. No spots on leaves no other problems just yellowing and not growing. Its as if it is getting way to much water. I started this plant in late June in a earthtainer using MG potting soil using the old Tomato tone and also garden lime. Any ideas what could have caused this problem? Thanks for any replies in advance.