Copyright by Jim Jensen. Permission granted to copy or post with complete attribution in whole, without addition, deletion, or substitution.

SUMMARY: The KISS - Keep It Simple & Save - plan for vermicomposting for farmers and others uses established methods (an extended windrow) and available equipment (a front end loader) to process large volumes of organic material into vermicompost. The plan suggests easy, appropriate technology to manage environmental factors and control quality. The KISS plan is based on several years of research and experience in vermiculture and vermicomposting. The plan may be adapted to other situations or applications.

BENEFITS: Farmers and others will benefit from several advantages of this method:

It is simple; no special training is required.

Low, low, low start-up cost - it uses existing equipment and available space.

No turning, no odors - the worms do all the processing, naturally.

The resulting vermicompost, rich in worm castings, is more valuable to farmers, landscapers, and home gardeners than raw manure. It provides stable organic matter, conserves moisture, improves soil conditions in many ways, and enhances the growth and yields of most types of plants. (Current market value is upwards of $30-$90 per cubic yard.)

STEP 1: WINDROW PREPARATION

A windrow is a long row of material (e.g., 4 to 10 feet wide, by 2 to 3 feet high, by some appropriate length). The length can vary depending on the availability of gently sloping space, ease of material handling, or other factors. Longer windrows will cost a little more for supplies.

To start a windrow, spread a 12 to 18 inch layer of manure solids, with or without bedding, along one end of your available space. Innoculate the windrow with high-quality redworms—Eisenia fetida (from a breeding or active pile). For this first row, apply up to 1 lb. redworms per sq. ft. of windrow surface area. Add 2 to 3 inch layers of manure every week (3 to 6 inch layers in colder weather) to gradually increase the depth of the windrow. Each windrow should be large enough to handle these thin layers of material each week. With a thermometer, make sure that the layers of feed do not get hotter than 35°C (~95°F).

Remember the following:

This plan is for farm-scale volumes of manure. Larger volumes can help protect the worms from adverse conditions and predators. Enclosed bins are still recommended for home- or school-based vermicomposting.

A hard or concrete surface is easier to work on, especially in wet weather, and may even be required to control runoff.

As you extend the windrow (Step 2), leave a way to reach the finished castings.
This method does not generate high heat. This is acceptable for many types of dairy and horse manure. If heat treatment is needed to control pathogens or weeds, simply precompost the material before feeding it to the worms.

STEP 2: EXTENDING THE WINDROW

After the first windrow is established and layered to around 2 to 3 feet thick, it is time to extend the windrow. Add the next layers of manure along one side, directly next to and against, the first windrow. The worms in the first pile will gradually migrate toward the fresher feed. Continue adding the fresh manure alongside until you have formed a second complete windrow. Repeat this step, extending the number of windrows to the limits of your need or space. The worms will continue migrating laterally through the windrows, leaving rich vermicompost in their wake.

STEP 3: MAKING QUALITY CASTINGS

Redworms tolerate a range of environmental conditions before suffering serious losses. Nonetheless, providing the optimum conditions for worm health and growth can assure maximum decomposition and transformation of organic wastes. Research from around the world and practical considerations suggest the following optimum conditions for redworms:

Temperature: 15 to 20°C (60 to 70°F)

Moisture content: 65 to 80 percent

Oxygen requirement: aerobicity

pH: > 5 and < 9

Keep the worms well-fed and comfortable, and they’ll make quality castings in the decomposed manure/bedding. Their active burrowing habits naturally aerate the windrows, providing good control of odors. Leaving each windrow for a little longer time before harvesting assures the vermicompost will be more broken down, more stable, and have more worm castings present.

STEP 4: MOISTURE AND IRRIGATION

Moisture is also critical to the well-being of your working worms. A simple method for applying moisture on a farm is through a sprinkling hose or other sprinkling/misting irrigation system. Run it the length of your windrow. Try to moisten evenly, i.e., keep the surface moist, but don’t let the bottom become soggy.

STEP 5: WINDROW COVER

A suitable compost cover, placed over the active windrow, is critical to preserving valuable nutrients in the vermicompost. Rather than nutrients leaching out and possibly contaminating ground or surface waters, they should be retained in the vermicompost in ways that are valuable for plants. Various types of tarps or fabrics could be used to shed excess rainfall and prevent leaching, while maintaining aerobic conditions. A few companies advertise fabric covers for composting. They may also be useful for vermicomposting. They include:

Top-Tex Compost Cover, from Autrusa Co., Blue Bell, PA, 610-825-2973, autrusa@aol.com

Compostex Cover, from Texel, Burlington, VT, 802-658-2958, wisluria@together.net

Compogard Cover, from W.L. Gore & Associates, Inc., Elkton, MD, 410-392-3300

Covering the windrows of finished castings prior to use also retains nutrients and helps prevent weeds from spreading.

STEP 6: HARVESTING

Because the worms concentrate in the freshest, most active windrow, after 2 to 6 months the first windrow and each subsequent windrow will become ready to use. It can be spread with a loader or manure spreader. Coarse material, if any, can be screened out to produce a fine, marketable soil amendment.