The question was raised about the use of only
partially composted manure in soil used to grow
edible crops. I replied that the International
Certification Standards specifically required that
manures be hot composted to a temperature of
between 120 and 140 degrees F for 6 weeks
before they could be used on certified organic
crops. The point being that composting manures
to destroy pathogens involves both temperature
and time.
Kira then posted:
> I can understand all this for carrots, potatoes, etc., >where the fruit of the plant touches the soil, but is >there any danger with peas, tomatoes, etc. where >the fruit does not come into being until long after >the plant has grown far above the ground? Will the >plant suck up the toxins and deposit them into the >fruits?
Don't confuse toxins, which are chemical agents, with
pathogens which are living organisms. Plants can pick
up toxic chemical materials from the soil and transport
them throughout their structure because these materials
can be incorporated into the plant's internal systems.
Pathogens, on the other hand, do not have to enter the
plant structure to be a problem. Pathogens can be
carried from the soil to the surface of the edible portions
of the plant by many different vectors. If there are viable
disease organisms in the partially composted manure
they are a potential problem. Washing of the produce
would PROBABLY eliminate those pathogens present
but not for sure.
All things considered, I think that it's just a better idea to
compost manures before using them in the garden.