Reporting
Yellowing leaves at base of plant.
I have a few plants that started yellowing at the base a few weeks ago. Others have followed suit. They all have several tomatoes on them. I've added Osmocote, cotton seed meal, and a fertilizer blend. It doesn't seem to be helping too much. One plant has 16 tomatoes on it. Another, the leaves are now turning brown in various places. There is basil nearby, as well as marigolds. What is causing the yellowing?