VERMICOMPOSTING DEVELOPMENTS

WORM FARM TAKES ON NEW CHALLENGES

Jim Jensen

Reprinted by permission from BioCycle Jan 1997 pages 56-57

NESTLED in a prairie on the western side of Mt. Rainier, between the cities of Olympia and Tacoma, Washington, the Yelm Earthworm & Castings Farm is one of the largest worm farms in North America, maintaining a population of redworms (Eisenia fetida) in excess of 15 tons. Started in 1990, on what previously had been a mushroom farm, the Yelm worm farm operated for seven years as a conventional worm growing operation-manure in, worms and worm castings out. In the spring of 1997, the farm was revitalized under new management. The emphasis now is on diversifying the farm's operations to take advantage of opportunities to add value to the farm's products. Accepting a wider array of feed sources is one step, while developing a broad range of complementary products and services is another. The farm is managed primarily as a seed source, for farm-scale and commercial projects in vermicomposting.

Facilities include 30,000 square feet of enclosed, warehouse type space with concrete floors and insulated walls. An additional five acres are available for expansion. Equipment on site includes a front-end loader, fork lift, conveyor, bagging line, two sizes of harvesting screens, and hundreds of stacking wood trays.

TWO PRODUCTION METHODS

The Yelm worm farm uses two methods to produce worms and worm castings. Mature breeder worms are grown in the four-foot by six-foot by six-inch wooden trays formerly used for mushroom production, which can be stacked to make more efficient use of enclosed floor space. About three or four times a year, depending on market demand, the contents of each tray are dumped and the worm population split between two trays. The breeder worms are fed separated dairy manure solids from a local dairy. Dairy manure solids are preferred because of their consistent qualities and ease of feeding to the worms in the trays. They also are efficiently processed by the worms and facilitate ready separation of the worms from their castings prior to packaging and shipping.

Bed worms, which include all ages of worms as well as unhatched worm cocoons, are grown in windrows using a feed mixture that can incorporate various proportions of organic residuals, such as dairy manure solids, chicken and horse manure, leaves and grass clippings. Preconsumer and postconsumer food residuals, being incorporated on a trial basis, make up a small proportion of the feed mixture. Depending on the mix of feedstocks used, this feed mixture is often precomposted. Precomposting is done quickly through two or three turns, which generate temperatures of 1400 to 1500 F. The temperatures are high enough to reduce possible weed seeds and pathogens, yet retain nutrition energy valuable to the worms.

After precomposting, the feed mixture is used to form extended windrows well populated with worms. The first windrow, 18 to 24 inches deep, is placed along one side of an enclosed shed. This windrow can be made with precomposted material seeded with worms or with the material from breeding trays. Additional feed is layered on this first windrow until it is about three to four feet deep.

Next, a layer of mixed feedstock, three to six inches thick, is placed along one side, directly next to and against, the first windrow. Though it may still be hot from the compost pile, the material cools quickly. As the material in the first windrow is converted into vermicompost, the worms in the first pile will gradually migrate toward the fresher feedstock. Each week fresh layers of feed are added, extending the windrow to the limits of space in each of the enclosed sheds. The worms continue migrating laterally through the windrows, leaving rich vermicompost in their wake. This system naturally simplifies the separation process, and the presence of older material provides an escape zone if conditions in the fresh material are too hot or otherwise unfavorable.

This extended windrow method forms the basis of a short, two-page plan the Yelm worm farm has published to introduce vermicomposting to dairy and horse farms. Known as the KISS (Keep It Simple and Save) Plan, it suggests easy, appropriate technology to handle manure, manage environmental factors, and control quality. For example, for sites without enclosed sheds, the plan suggests use of compost row covers.

MAIN MARKETS

The Yelm worm farm focuses on three primary markets for worms and worm castings: home gardeners and composters; resellers, such as nurseries and distributors; and farmers, especially organic growers. In addition to classified advertising, direct mail, and word of mouth, the Internet now plays an important role in marketing. As many as half of the small orders for worms are generated from the farm's Internet website. The farm also arranges to supply somewhat larger quantities to home composting education programs for distribution to the public. Bulk orders of worms - hundreds of pounds at a time- are shipped throughout the western U.S. and Canada to start new vermicomposting projects.

Worm castings represent another important source of revenue for the business. Markets for castings are more localized than the market for worms because of the weight involved in the added costs of transportation. This can be advantageous for the numerous farmers and entrepreneurs considering vermicomposting as a business opportunity. Even if they are only 30 to 50 miles apart, several producers can operate in a region without overlapping their markets significantly. Castings production capacity is several thousand cubic yards per year. In bulk form, vermicompost sells for two to three times the price of local compost, or six to 12 times the value of raw manure.

Many soil specialists recommend that worm castings be used as supplements with other soil amendments, such as compost, rock powders, and minerals. Small amounts of castings go a long way by contributing to the effective use of each of the various soil amendments. Managers of the Yelm worm farm expect that the vermicompost derived from the mixed feedstocks will have the finer, darker look that people often expect from earthworm castings.

As an important development in the markets for worm castings, the Yelm worm farm is forming partnerships with other businesses that market products for soil improvement and restoration. Experience has shown that sales for such products are strongest during the spring gardening season. In 1998, Yelm worm castings will be marketed in bulk and bagged forms next to and mixed with other soil amendments.

Jim Jensen has been involved with vermicomposting for 10 years. As a consultant with Sound Resource Management Group, Seattle, Washington, he developed custom solutions for institutional vermicomposting. He is the chief executive of the Yelm Earthworm & Castings Farm.

BioCycle Jan. 1998 pages 56-57