Hey everyone, I'm a first year gardener in south florida and I'm having issues with my tomatoes. I'm growing pink brandywine and phoenix varieties and all three of my plants have some similar problems. As the plants grow, the new growth looks green and healthy but the older leaves gradually get yellow and brown areas on the top and brown spots on the bottom until the leaf dies. And, the plants would flower repeatedly but drop them before setting fruit. Does anyone know what's wrong and how to remedy it, preferably with a natural/organic method? Thanks so much