Hello Tomato Experts! I've scoured this forums for the past couple of years as I've expanded the garden on my balcony up here on the 24th floor in Brooklyn. I'm growing my Abe Lincoln in a grow bag (with a cage) using organic potting soil mixed with compost and a bit of fertilizer. Just recently the lower leaves of my (already huge) plant started turning yellow:

I'll post more below, but my plants live 24 floors up and get TONS of sunlight. I've already got a few tomatoes developing. I recently side dressed them and it didn't seem to help. Today I cut off the yellowed branches and watered Abe with some Epsom salts (1T per gallon). Hopefully that will fix 'em. Please let me know if you have ideas about what might be wrong. Here are some more pics from various stages of yellowing.