I'mm not sure what is going on with my plants, there seems to be ten thousand explanations online and none of them seem to fit perfectly. I live in Los Angeles in an apartment so I grow my organic brandywine tomatoes in a "spa" pot that you water from the bottom. They were doing great until they started to flower, when the bottom leaves began to yellow. I cut off all yellowing and this continues for some weeks but now there just seems to be an overall wilt with dark blue/black spots on the leaves. The stems are turning brown in the middle of the plant--they are green at the stem and green at the very top but the middle is brown. I cut some stems and the inside was perfectly green. I found brown dust on my hands from handling affected stems but was not able to "rub off" the brown color, so it wasn't just the dust. I grew this plant from a seed and feel sorry to see it doing so bad. Should I start all over or is this plant salvageable? Here's photos: