Planning For Spring - Blight

[TFA303]

In one of my raised beds, I almost lost my tomatoes to what I think was Early Blight, and I did lose the zucchini.

Is there anything I should do to prepare the soil so that I don't have the same problem next Spring?

Ditto for Powdery Mildew in another bed.

Thanks in advance for any suggestions!

[Chris]

Consider using a systemic fungicide from the getgo next year.