Perennia hosted a workshop on Tuesday, May 17th,
2016 at the Wolfville Farmer’s Market.
In attendance were some of Perennia’s summer students. Jonathan Bent, Tamara Dondi, and Jessica
MacDonald have written up a brief overview of the morning’s discussion.
Dale Overton, President of Overton Environmental
Enterprises Inc. (OEE) situated in Manitoba, held a talk in Wolfville, NS outlining
the science behind Eco-Tea. Eco Tea
is actively aerated compost tea, infused with an organic blend of humic and
fulvic acids, Atlantic kelp extract, complex carbohydrates and enzymes. Humic acid can be found in compost and acts as
a chelating agent, which increases the availability of nutrients to plants and
prevents nutrients from leaching.
Eco-Tea
is made from four different types of compost. To reduce the number of
pathogens, the compost goes through a thermophilic stage where it is heated
enough to work against the growth of pathogens.
When making the compost it is essential that air (oxygen) is allowed to
move through the pile because anaerobic conditions (no oxygen) favour the
development of disease. The compost aims to support the growth of a complex
microbial community which will outnumber pathogenic organisms.
A broad definition of
compost tea is that it is a liquid extract of compost. In general, compost tea
contains nearly 20,000 different species of microorganisms. Similar to when
making compost, the goal when brewing compost tea is to produce conditions in
which beneficial microbes can grow.Other things can be added to the tea as well, such as grain meals (food for the microbes), minerals, and bio-stimulants. Bio-stimulants are not added to the compost until the end to allow enough time for the beneficial organisms to build a complex community.
If a fungicide is being applied, Dale recommends waiting
to spray the tea for 5 to 7 days to limit the detrimental effect of the
fungicide on the beneficial microbes in the compost tea. Sprays should go on either before 10:00 am or
after 6:00 pm using a field-jet nozzle, with no filters. For transplants, he
recommends a 50:50 dilution in water.
For more information about compost tea, please check
out this eXtension webinar: http://articles.extension.org/pages/73211/making-and-using-compost-teas
*** Note that compost teas can pose a food safety risk.
To minimize the food safety risk, only use compost tea produced under
conditions that are not a source of biological (e.g., pathogens), chemical
(e.g., heavy metals) or physical (glass) contamination, and with a documented
composting procedure. Compost teas are
approved for use under the CanadaGAP Food Safety Program but their use does require
that a letter of assurance from the supplier be filed with the CanadaGap
records. For additional information refer to Section 4 and Appendix C of your
CanadaGap Manual. ***
