I am sure BLIGHTs are not soil borne. But I am not sure about the wilt. But at any event, you can use the soil to grow variety of other plants like, pepper, eggplant,squash, cucumber, herbs.. etc. Just pull out the root and get rid of it.

Wait for more comments.

seysonn, thanks for your reply. So I do not need to be concerned about using the soil again for any other plants in genus Solanum? I was thinking that I needed to "rotate" the soil, like we rotate crops planted in the ground. My understanding is that practice is not only for soil borne diseases but also pests that attack the same genus of plants, but maybe I'm wrong or that's not an issue with container soil?

You might want to check out this thread in the Organic Gardening forum.

Here is a link that might be useful: GW Organic Gardening forum

Both early blight and tomato wilt ARE soil borne. Late blight is one of the rare fungal pathogens that does not reside in the soil - it is usually transmitted by infected plant material or live spores can blow in with wind and rain storms. However, since the widespread severity in the outbreaks of late blight in home gardens since the late 90's, it has been determined that new strains of the late blight fungus may have spread to many areas. Some of these strains may interact and form a type of resistant spore that can survive for long periods in soil.

The persistence of these pathogens in the soil is the reasoning behind the recommendation for crop rotation. The soil can be reused but I'd caution against using it for anything in the Solanaceae family.

elc, my answer to your question in your post is at the bottom of this post but please do read what I've posted first.

Blight is a general word that to most folks means a sick tomato or potato plant/

There are the fungal foliage diseases of Early Blight ( Alternaria solani) and Septoria LEAF Spot ,, and the two bacterial ones Bacterial Speck and Bacterial Spot, and NONE of them are soil borne diseases/

The spores of the first two and bacteria from the second two may fall to the soil from infected plants and the next year be splashed back onto the lower foliage after heavy rains or irrigation and that's called splashback reinfection.

There are many other diseases that do cause wilts, the foliage diseases do not, and the most common wilt dieases of Fusarium and Verticllium are soilborne and Root Knot Nematodes in CA and the south where the gound does not freeze deeply and areas. I repeat, where the soil does not freeze deeply/

There are two major mating types of LB (Phytopthera infestans a systemic disease) now, before about 199o, as noted above, and before that there was just one.

This gets a bit complicated so I tried to find some links that would explain it best rather than my doing a lot of typing.

Both mating types A1 and A2 are now found in the US and are most predominant in the middle Atlantic states and especially the PNW/

When the two mating types meet they can form oospores that can overwinter whereas the LB most of us know cannot.

Oospores can give rise to recombinant strains or LB that have more tolerance to to the antifungals that commercial farmers use, the most important one being Ridomil, which is not available to home gardeners.

The best prevention for home gardeners is Daconil.

And now it's time to get some links going so I don't have to go through the life cycle and so much more.

The first link which is at the very bottom does a good job of explaining the situation in non-technical terms.

Here;s a second one from MI that is also non technical.

http://migarden.msu.edu/uploads/files/e1802.pdf

Elc, you mentioned both blight and wilt in your initial post. You said that it was new soil, so one has to assume it had NO foliage disease spores or bacteria in that new mix, and it wouldn't have had any soilborne wilt pathogens either,

So I have to assume that what your plants had were one or more of the fungal foliage pathogens that are spread via wind and embedded in rain droplets, or from irrigation.

Yes, I know CA and occasionally it does rain and yes the wind can blow in spores from other areas.LOL

If those foliage pathogens dropped onto your container soil then yes, they could be a problem next year , the same as if you were growing inground as to splashback reinfection, so what you can do is to remove maybe 4-6 inches of that possibly contaminated mix and top it off with new mix. Or if money is not a factor, dispose of the mix in the containers and replace with new.

If it were me I'd remove the several inches and top it off.

All NEW infections with the fungal and bacterial pathogens are acquired via wind, rain or irrigation as I mentioned above, as opposed to splashback reinfection.

Hope the above helps,

Carolyn

Here is a link that might be useful: LB mating types and more