How do I get rid of the diseases for fall crop

[Fiishergurl]

I am going to pull all of the rest of my plants in a couple of weeks. Everything is growing in self watering containers with potting mix, perlite, vermiculite, plastic covering on the top and mulch on top of that.

We have had terrible leaf diseases... grey mold, powdery mildew, and something that made the leaves yellow and then turn brown and worked it's way up the plants that didn't get the mold.

The containers are either on concrete or on grass and some are staked and some are growing against trellises.

Can I sterilize things enough (stakes, used velcro tape, trellises, concrete, etc) enough that my fall babies won't get the diseases? It will still be humid and hot by the time I put the new seedlings out so I want to try to clean things up as much as possible before that happens.

I do plan to scrape the topsoil (2 inches or so) off each container and replace the plastic and mulch.

Thanks for any advice!

Ginny