Last year my tomatoes developed black spots on the leaves and from what I've read about all the possible diseases, they can stay in the soil. Is there anything I could do to get rid of it? Do I need to change the soil in the garden?
Certified GKH Gardening Expert
You can either rotate the tomatoes (and other nightshades like potatoes, peppers, and eggplants) out of that soil for a season or two and let the disease die, or your can solarize the soil to kill the disease. These are really your two best options for dealing with tomato bacteria and viruses. Here is some information on solarization: