I’ve had some kind of illness with tomato plants and it spread in a way that is pathogenic where a 3rd plant was kept separate but upon leaving in closer proximity it become infected. I thought the first two were due to some circumstantial factors like using some soil from another plant that died, or pots with poor drainage, but the third plant did not have these factors. So am I forced to clean surfaces, toss the soil and start over, or can I reclaim the soil?
Don’t “sterilize” anything. There will be many resilient microorganisms surviving which are just waiting to take over anything when they have the chance to.
You should add some beneficial microorganisms, often sold as mycorrhizae, and take a look at living soil. A few worms or critters here and there are also great!
Soil should regulate itself, but you can give it a small headstart.
Regularly add some compost or dead plant parts, symbiotic plants, and so on.
If you don’t like dirt, as I see it a bit in your “keeping everything clean” mentality, maybe come over to !hydroponics@slrpnk.net.
I tried hydro this season, and I was so amazed that most of my stuff next year will be grown hydroponically!