You can tell Jim is still in Florida with his description of soil
solarization....

It should be called soil pasteurization, because the temperatures
reached will kill pathogenic organisms, but not thermophiles (the kind
of heat-tolerant bacteria that accumulate in composted material). It
is a technique used commercially in Israel, California and Florida.
All of which have hot summers.

We tried soil solarization in our fields on Long Island, with horrible
results: our clear plastic was difficult to anchor and the wind kept
blowing it away or tattering it. Long Island can't support early
summer solarization (with mid-summer planting of crops like spinach or
squash) because the summer doesn't get really hot until July and
August. So the temperatures under the plastic were nowhere near as hot
as they ought to have been.

So anyway, Martin, your easiest course of action is to let the soil dry
out. That will kill most of the pathogens.

One of my research goals is to find a way to clean up potting mix from
contamination by the "sudden oak death" pathogen. So check back with
me in, oh, 10 years and see what I've come up with.

Nina.