Someone replied to my last post on Early Blight, “Will this contaminate the soil (for next year)?” Great question. Here is more info on this subject.
If you have a garden, it’s pretty much in the soil. One key is to provide a barrier between the soil and your plant, hence I add straw as a mulch around them to act as a barrier and use fungicides to catch it early or before it starts.
Some years are better as they are drier but when you have a wet summer, it can be a problem. I’m not sure if you took out the soil if that would help because who can remove all the soil? Unless you put them in pots-maybe that would work.
You should consider crop rotation, not growing in the same spot for 2 years and then coming back to it 3 years later. Crop rotation is used to control diseases that can become established in the soil over time. Changing your tomato crops to a new bed or area tends to decrease the population level of the pathogens. That is why I have 3 sections in my garden so I can rotate the tomatoes to a new section each year. If you have raised beds, you could rotate the tomatoes to a new bed each year coming back to the original bed 3 years later to get the same effect.
I don’t look at Early Blight as a major killer of tomato plants if we do close monitoring and take action. By using fungicides early on and crop rotation every year, we can usually control it.
Also good clean-up in the fall after the garden is done is important. Do not compost the dead plants but bag them and put in the garbage.
You can read the first post about Early Blight here.