This is my second year trying to grow tomatoes on my balcony. Last year went alright but had some end rot on my romas. This year all 3 of my tomatoes have leaves that are turning brown like this. Can anyone tell what would cause it?
Yeah that'll do it. I'd dig them up, remove any rotted roots, fix the soil, and repot. Plenty of options like perlite, coarse sand, tree bark. And make sure you don't compact the soil by packing it down when potting.
Edit: also the other question about fertilizer. Could be too much. Likely not too much sun, since you said it's been cold and rainy.