TALKING SHOP: Washington Tilth Producers Conf., Nov 7-9 Bellingham, WA

Part 1 of 3: Microbes: THE hot topic at the Washington Tilth Producers’ annual conference
Our researcher and reporter, Don Lotter, wandered the halls and seminar rooms of the conference, gathering details on everything from a really inexpensive compost tea brewer to the growing of fungi that first attract, then later kill insect pests.

By Don Lotter

S p o n s o r B o x
Meet the Washington Tilth Producers

Mission/members: Tilth Producers, a Chapter of Washington Tilth Association, is the organic and sustainable farm organization of Washington State. A membership organization of over 400 Washington growers, Tilth Producers fosters and promotes ecologically sound, sustainable agriculture in the interest of environmental preservation, human health and social equity.

Founded: In 1974 off the back of a letter and vision of Wendell Berry, the group has suffered through highs and lows. Today it is regrouped and refocused on its mission: unite the community of people concerned with food, agriculture and the environment. For the complete history>

Mail: P.O. Box 85056, Seatle, WA 98145

Contact info:

Nancy Allen,
Administrative Director
(206) 442-7620
Fax: (206) 524-7702

Coming soon

Part 2: direct from the Tilth conference:

A Washington State organic program rep reviews the rules on mating disruption pheromones, compost, compost tea, livestock feed and international compliance. Part 3--Innovative small acreage tools, from a strap-on stool for hand weeding to a hand-wheeled flame weeder. Mustard as a biofumigant and cover crop. Tips on producing organic seed.

November 17, 2003: Microbes are the hottest topic and yet the least known aspect of organic agriculture. The U.S. northwest has for years been the epicenter of compost tea research and use in North America. Below I relate some of the things I heard at the conference – whether during hallway discussions, in the dining room, or from speakers at seminars.

The inimitable Bob “Amigo” Cantisano of Organic Ag Advisors and Aeolia Organics of North San Juan, California, presented a design for a compost tea maker that costs just a few dollars (plus an air compressor), and is yielding compost teas with microbe counts that are higher than the counts from expensive compost tea makers. Here is a rough description of it. (Disclaimer: this description based on Amigo’s diagram and explanation at the dinner table is limited in its details. If you want to make one you should contact Amigo for more details at

Run a hose into the bottom of a barrel (i.e. 55 gallon drum), and there connect it to a soaker hose. Connect the other end to an air compressor. Fill the barrel with water to roughly ¾ capacity. Don’t forget to aerate the chlorine away. Securely attach some shade cloth (cheap and effective mesh) around the top of the barrel in such a way that when compost is put into it, the aerated water bubbles up and soaks the compost but doesn’t submerge it. The water level should be just below the sagging shade cloth with compost. That’s it. Amigo uses 10:1 weight to weight of water to compost, or 30-35 lbs compost per 45 gallons of water (about what a 55 gallon drum would hold for this setup). The soaker hose, according to Amigo, makes a fine air bubbler.

Alison Kutz-Troutman of Sound Horticulture in Bellingham, WA (, related her experiences with controlling powdery mildew in greenhouse-grown plants with compost teas. Alison uses kelp extracts as a compost tea additive and also side-dresses with azomite, a rock dust product widely available from organic product suppliers. She thinks that bi-weekly or even tri-weekly applications of compost teas are sufficient. Alison related a story about the effectiveness of her compost teas in controlling powdery mildew. While she was away on a trip, her greenhouse-grown sage plants were left unsprayed, and were 90% covered with powdery mildew when she returned. She applied undiluted compost tea twice a week and within a couple of weeks mildew was completely gone.

Swearing by kelp

Several veteran organic farmers I talked to swear by kelp products, whether in compost teas or as a stand-alone foliar spray. Nearly all of the kelp extracts used in agriculture come from the common North Atlantic kelp species Ascophyllum nodosum. Kelp contains some 60 naturally occurring major and micro nutrients, carbohydrates, and 18 amino acids, vitamins and naturally occurring growth promoting substances. Mannitol, a chelating agent that potentiates the transport of cations like calcium and iron into plant cells, is one of the primary beneficial compounds in kelp.

A number of companies harvest kelp from the coast of Nova Scotia where the tides fluctuate by 20-30 feet. Kelp under these conditions is alternately dried out, frosted, stretched, and wetted, and therefore contains a number of compounds that apparently enable plant cells to withstand these stresses.

Bacterial inoculants

Lynn Rogers of Microbial Matrix Systems in Oregon (, just this year opened a laboratory for analysis of composts, compost teas, and soils. Lynn worked for Elaine Ingham before deciding to go her own route. Lynn says that she has had excellent results from inoculants containing plant growth promoting rhizobacteria (PGPRs).

PGPR can be a number of genera, but the most common ones are the fluorescent pseudomonads (Pseudomonas fluorescens) and Bacillus subtilis. The inoculant Lynn used is still under proprietary development, but dozens of companies sell PGPR inoculants. Lynn adds the PGPR inoculant to her compost tea after the brewing and uses it as a soil drench. She says she gets potatoes three weeks earlier and with fewer lesions by using the PGPR inoculant.

New compost tea organizations

At a round table on compost teas and agricultural microbes, Cindy Salter of Growing Solutions (compost tea equipment and additives) in Oregon described two new organizations started in the northwest. The Compost Tea Industry Association (, out of Eugene, Oregon, got going in January, 2003. The CTIA will provide a forum for information exchange and marketing opportunities for products and services within the rapidly growing compost tea industry. The Compost Tea Education and Research Foundation will, which has not yet been officially formed, will focus more on research on compost teas. For more information contact Cindy at


There was talk about the state of the art of vermicomposting. The word is that Jack Chambers of Sonoma, California, is the cutting-edge practitioner. Chambers is on the board of directors of the CTIA. He uses “separated dairy solids” (dairy manure), plus various carbon sources, and has a pre-worm, thermal composting stage in which he forces air through the mix. Then just as the thermal composting rate slows and temperature begins to decline, it is put into the worm stage.

Rich in fungi: Paul Stamets turns the conference-goers on to fungi, all aspects of them. His hat is made from a fungal "conk". Paul unveiled his invention of a fungal pesticide whose potential is so huge that several billionaires flew in their private jets into the little rural airport in western Washington where Stamets lives to convince him to let them invest in a company to commercially develop the idea.

Insect control using fungi: The amazing Paul Stamets of Fungi Perfecti in western Washington ( gave a keynote speech as well as a packed-to-the-rafters workshop on the role of fungi in, well, life. Paul related his recent development of a mycoattractant cum mycopesticide, essentially a process for growing common entomopathic (insect-lethal) fungi in such a way that insects are actually attracted to it. He related the story of how he treated carpenter ants in his house with it, and they completely disappeared. Then gave his aunt some, and the carpenter ants completely disappeared from her house as well.

So apparently huge is the potential of Stamets’ mycopesticide patent that several billionaires flew into little Shelton County airport in their private jets, one by one, to meet with him and try and convince Stamets to let them be the primary backer of whatever company he starts.

Stamets related how he negotiated with the investors about necessary ethical principles that would need to be adhered to by any company he is involved in. This means 1) the company will not be involved in the eradication of insects by using plague-like organisms (his invention is not spread like a plague organism); 2) protocols must exist to make sure that the product is accessible by low-income communities, 3) some of the profits go to non-profit organizations, and 4) the intellectual property rights of native peoples must be respected, i.e. profits from products derived from traditional native herbs or organisms must be shared with those peoples.

The core of Stamets’ mycopesticide process is to culture the entomopathic fungi in their pre-conidial stage. Up until now, entomopathic fungi have always been used on insects in their conidial (spore) stage. A number of products and patents have been developed for such common entomopathic fungal genera as Metarhizium, Beauveria, and Paecilomyces, names that anyone working in biological control recognizes. The problem has been that the conidial stage is highly repellent to insects, and is the form that up until now, has been used to dispense entomopathic fungi.

What Stamets found was that the pre-conidial, non-sexual, hyphal stage of the fungus, which has long been ignored by mycologists because it wasn’t active against the insects, is highly attractive to insects. “The fungus knows that the insects know that the conidial stage is lethal, so it produces a form of itself that is attractive” says Stamets. Then, when the insect takes the mycelia to its colony, the mycelia sporulate in the warm, moist conditions of the colony, and produce the insect-lethal form of itself.

Stamets related how his aunt found the carpenter ant queen and her worker-ant minions in a swarming pile on the carpet after the bait fungal mycelia had been taken away by the ants. The colony had become so toxic that the ants abandoned it and brought the queen out into the open. After flushing them down the toilet, they haven’t come back.

Stamets believes that there will be numerous applications of this process in agriculture.