There aren’t a lot of scientifically-conducted research results available that reference vermicompost tea. Plenty of anecdotal stuff. I know what I believe, what I’ve seen with my eyes, but still, study results make one feel a little more confident in his or her course of action.
I found this pdf, reprinted from BioCycle referencing Ohio State University studies:
“Greenhouse plant growth trials… established that the vermicompost teas had significant effects, not only on plant germination and growth, but also on the incidence of plant diseases, plant parasitic nematodes and arthropod pests.”
That feels better.
“…half of the treatments tested were aerated and half were not. Parameters studied were: pH, ni- trate-N, dehydrogenase enzyme activity and microbial biomass. All of these parameters were significantly lower in the nonaerated teas compared with those in the aerated ones, probably be- cause dissolved oxygen supports microbial activity.”
“Germination rates, heights and leaf areas of tomato plants were significantly greater in response to treatments with aerated vermicompost teas, than those of plants treated with nonaerated vermicompost teas”
“There were significant growth responses to aerated vermicompost teas, even at the lowest concentration tested. Similar responses occurred in germination, heights and leaf areas of cucumbers in response to aerated and nonaerated teas. No practical problems such as adverse growth effects in the use of vermicompost teas were found at any of the dilutions tested.”
And that makes a good case for aeration.
And this, from BioCycle Magazine
“Preliminary research has demonstrated clearly that teas produced with aeration are much more stable and effective than those produced without aeration”
“During the “brewing” process, soluble mineral nutrients, beneficial microorganisms, humic and fulvic acids, plant growth hormones and plant growth regulators – known to be available in solid vermicompost – are probably extracted into the tea.”
“In more recent experiments, we applied a range of dilutions of teas produced from cattle waste vermicompost, to tomato plants infected with Verticillium wilt and assessed the damage ratings after 14 days. All of the application rates of teas that were tested suppressed this plant disease significantly.”
That last bit, about plant disease suppression? It seemed to be the case for me last year. My tomatoes have never been healthier.
The only hesitation I have is that my experience using aerated worm tea only encompasses one year. Growing conditions, especially the weather, probably affect results as much or more than other factors. Last year for us in southeastern Michigan was one of the best weather years I can remember.
So as much as I hope and believe that aerated vermicompost tea really makes a difference, I should probably cool my jets for a year.
If you come across anything, I’d love to see it.