Tomato problems?

Tomato problems?

Help! I'm trying tomatos this year in a pot (they were labeled as patio sized at Lowe's). So far so good. They've grown, and I have one tomato that is about 2.5" in diameter already, plus a bunch of flowers, so I think they're growing well. Problem is, the leaves are yellowing and drying up from the bottom up-I've been trimming off the damaged leaves as they happen, but it's continuously happening, and I'm only about 3 levels down from the existing tomato at this point. If it keeps happening, I fear I'll lose the one tomato I already have. Any ideas? Sorry I don't have a photo of it, our camera's out of commission today....
Hawaiian Schefflera

Hawaiian Schefflera

tomato sprouts

tomato sprouts

Terrace update

Terrace update

Some kind of lily.

Some kind of lily.

hi

hi

mold and plan id

mold and plan id