I live in Los Angeles and have a small yard with a garden big enough for me to grow about 12 tomato plants every year. I know that planting in the same spot every year can create issues for plants, but as I only have one area where I can grow I don't have the option of growing somewhere else. Every year I try my best to amend the soil to protect against anything that might be lingering in the soil from years of planting in the same spot. But every year I have basically the same issues... about midway through the summer, usually around mid July, my beautiful green plants start developing leaf issues which end up ultimately killing off the plant. Sometimes it is a wilt, where the leaves start to go limp from the top and then start to wither their way back down the plant until the whole branch then eventually the plant dries up and dies. I also have issues that are probably from an airborn pathogen, where leaves start yellowing in spots, which then spread through the leaf then clusters of leaves then backward through the plant. I don't think this is blight as the weather in Southern California is generally very dry and blight tends to result mostly from higher humidity areas. I'm guessing I have a mixture of fusarium or some soil wilt, and perhaps some other airborn fungal spor, either a powder mildew or something like that.

Anyway, I've taken down my plants for this year and want to try some preventative measures for next year. I've heard recommendations of planting a winter crop of beans to enrich the soil. But is there something I can add to the soil to treat against soil born pathogens? An anti fungal or anti bacterial soil drench?

All recommendations welcome!...Thanks in advance.

Don