We’ve
all heard the expression “garbage in, garbage out”. That
expression can be applied to compost tea production also. What comes
out of the brewer at the end of the brew cycle depends to a great
extent on the compost you start with. That is why it’s
important to have a good quality compost in the extractor to begin
with. By good quality, I mean densely populated with diverse
beneficial microbes. Compost should have thousands of species of
bacteria and fungi, as well as multiple species of protozoa.
Nematodes are also beneficial but they will not multiply in the
brewer, so what you put in will be what comes out. Compost that is
good enough to be the basis for good compost tea is what we call
extraction grade compost. Some of the best extraction grade compost
starts with vermicompost (worm compost) as a base and has other types
of compost added. We use vermicompost in most of our brews because
most of the studies on the effectiveness of compost tea as a disease
control factor conclude that vermicompost shows the most benefit. We
will detail a method of creating your own back yard vermicomposting
operation in a future edition of this Newsletter.
Sometimes
we want to create a compost tea that is higher in fungi than we might
see in vermicompost. In this case, addition of fungal wood chips can
help boost the fungal component of your compost tea. What are fungal
wood chips? Certain high lignin hardwoods, when properly shredded and
stored will promote the growth of beneficial basidiomycete fungi.
These saprophytic (digesters of dead organic matter) fungi are very
important in soil nutrient cycling and seem to help in suppression of
root rots. I have found finely shredded oak branches to be very
effective at building fungal biomass. The fungal hyphae will
interpenetrate fungal chips to the extent that a solid block of wood
chips is bonded together by the hyphae and we have to tear chunks off
the block. In some cases, we see mushroom formation. Use about 15%
fungal chips (by volume) in the vermicompost blend.
As
to nematodes, I have found that certain kinds of fruit pulp
concentrate are good sources of nutrient cycling nematodes. So,
addition of a bit of the fruit pulp can introduce these important
members of the soil food web into your compost.
Once
the compost has been blended, we often activate it for a few days
before we brew the tea. I use a 50-50 blend of Azomite rock powder
and organic oat flour as an activator. This complex
carbohydrate+mineral blend tends to boost the number of active
microbes in the compost and increase fungal hyphal growth. You can
use about 5% by volume of this mixture as an activator. Mix it well
with the compost blend, wet the mix to about 40-50% moisture level
(it clumps well in your fist but you can squeeze out a drop of water)
and store it in a dark, covered (loosely) container for a few days.
You should see fresh fungal hyphae growing on the shredded wood chips
when the compost is ready to use. If you are using a microscope, you
will see plenty of active bacteria and growing fungal hyphae in the
mix.
ORGANIC
LAND CARE REPORT
The
Oregon Tilth Accredited Organic Land Care program continues in it’s
development. Tilth has signed a contract with form Tilth Education
Center Director Andy Parker and Bruce Nelson of Clackamas Community
College to develop the all important organic practitioners field
guide. It is also anticipated that Clackamas Community College will
develop and host the annual week-long training session. The down
side of all of this good news is that the program has been put back
another year. It is now scheduled for introduction in January 2010.
However, Oregon Tilth plans to offer a one day introductory workshop
for our professional partners in sustainability next fall/winter to
fully inform and prepare our partners for the program when it is
introduced. What is even more exciting is that the US EPA is about
to introduce a certification seal for nursery products and landscape
practitioners and may use the Oregon Tilth Accredited Organic Land
Care training and standards as part of their program. If this
happens, the Tilth program may draw landscape professionals from all
across the country. The Tilth program, together with the US EPA
program should help early adopters of the organic approach to
landscape practices be well positioned to build market share in the
future.
