Getting ahead of blights

[flying mater]

I asked this question over on the GW site and thought I would ask here as well. Hope I'm not over doing it.

Here is the question. is there anything that I can do now to my garden soil to help prevent blight for next year? I've read were adding corn meal helps and will be doing that. But is there something else i can be doing to clean up the soil from pathogens?

Also, If I save seeds from these infected plants, will the seeds be infected as well?

Thanks for any advice.

Bill