[USCC] concentrated compost tea brews

[Allison L H Jack]

Hi Kelly,

You are right to be skeptical about these kinds of products. I'm doing my 
doctoral dissertation research at Cornell in Plant Pathology and I work 
with the microbiology of vermicompost and non-aerated vermicompost teas. 
 From 6 years of scientific literature searches, I can tell I have found 
nothing in a peer reviewed journal about concentrated compost tea mixtures 
with dormant bacterial cultures and their effects on plant growth and/or 
health. If anyone on the list has found a reputable reference on this 
topic, please let me know. With that said, I will mention that many of the 
individual microorganisms with the ability to suppress plant diseases are 
spore-formers (Bacillus spp., etc.) so there is a possibility that this 
product does contain dormant beneficial bacteria. The problem is that the 
number and diversity of known beneficial bacteria does not correlate with 
disease suppression when you are working with the kinds of complex 
microbial communities found in compost and compost teas. There is just so 
much we don't know in this field and very few people are working towards 
scientifically sound answers.

I'm currently conducting on-farm field trials with vermicomposted dairy 
manure as a potting media amendment. One of the growers we're collaborating 
with wanted to try what sounds like a similar product (Alaskan humified 
something or other), so we added it into the trial. I'll be assaying the 
material for its ability to suppress Pythium damping off, so I should learn 
something useful about the microbes in this product. We just started the 
project and when I get the website up, I'll share it with this list. We'll 
be posting a lot of our results as we go along.

-Allison


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Allison L H Jack
Graduate Student
Department of Plant Pathology and Plant-Microbe Biology
http://pppmb.cals.cornell.edu
Cornell University
335 Plant Science
Ithaca, NY 14850
607.273.5762
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