Organic Transitions
Willamette Organics Quarterly Newsletter
Volume 3, Issue 3 Summer 2008

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Extraction Grade Compost

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.



Coming Next Edition!

Liquid Compost Extractors

Terra Preta Soils

Making Vermicompost





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