Vermicomposting: Worms are wonderful!

There’s no doubt about it. Worms are yucky! They’re squishy and slimy and ugly and better left in the ground where they belong. But what they can do for your soil is positively beautiful.

Vermicomposting is catching on. I interviewed Betsy Lynch of Good Earth Worms, who with her husband, Matt von Riesen, bought 35 acres north of Fort Collins on what used to be the Shamrock Ranch. As avid organic gardeners, they were committed to planting trees, fruits, flowers and a large vegetable and herb garden, but found that, having been conventionally farmed for years, the soil was depleted of nutrients and about as tillable as a concrete sidewalk. Betsy and Matt found that they really couldn’t grow anything very successfully. Being horse people, they had plenty of manure for fertilizer, but in the dry Colorado climate, it can take a long time for horse manure to break down into an effective soil amendment. That’s when a friend suggested that vermicomposting might be the way to restore their depleted soils. In 2008, Greg Krush, a local tree farmer, mentioned that John Anderson was using earthworms bedded in horse manure to produce a superior compost. Intrigued, Betsy and Matt bought their first supply of worms from John.

What the worms do is to consume organic matter, process it through their wiggly little bodies and then excrete the “castings” (you can also call it “poop”) as a rich, crumbly amendment loaded with plant nutrients. However, it’s not just the worms that perform this transformation. It is a complex matrix of organisms that work together to create the soft, dark and highly stable humus referred to as vermicompost. But that’s not all they do. Worms can actually reduce or even eliminate environmental toxins in the soil, including chemicals left over from synthetic fertilizers or industrial waste.

While all worms make castings, not all worms are suitable for vermicomposting. According to Betsy, Eisenia fetida, (sometimes called red wigglers or small redworms), are the best species for the task. They aren’t endemic to Colorado, and they don’t actually live in the ground. They’re litter dwellers that reside in the organic matter above the soil surface. In contrast, the common night crawler, lives below ground, sets up permanent burrows, and does not like to breed in captivity. (Incidentally, it’s not a Colorado native either.)
It’s a simple process, but Betsy and Matt have to create the environment that enables the redworms to do their job. The critters need 80% moisture. Betsy and Matt cultivate the horse manure first by pre-composting it (allowing it to heat up) in order to kill weed seeds and potential pathogens. After that, the manure is ready to go into the worm beds to be thoroughly processed by the worms and a full complement of microorganisms.

Vermicompost is different than traditional (hot) compost in a number of ways. Worm castings provide a greater number and diversity of soil microbes. They provide five times more plant available nitrogen than the “hot” compost. They provide a slow release of plant available macro and micro nutrients. Seeds sprouted in soils enriched with vermicompost almost always germinate more quickly and the plants and roots grow more vigorously. Vermicompost is also effective in the suppression of plant pathogens and the creepy vectors such as aphids, spider mites, mealy bugs, tomato horn worms and cucumber beetles, among others.

Betsy was no stranger to the science of agriculture. She earned her Ag degree from CSU in 1980, but was discouraged by the industrial approach that was taught at that time. There was really no organic alternative available then, as there is now. Once she discovered how effective vermicompost was in her own gardens, she tapped her inner scientist and began to research what it is that the worms do that make castings so effective. She attended North Carolina State University’s Vermiculture Conference and the U.S. Composting Council’s Conference to learn as much as she could from experts. The more she learned, the more she saw the possibility of starting a business and sharing her knowledge with the rest of the community.

Betsy and Matt hold workshops at local nurseries, schools, and community events. A visit to their website at provides detailed information about vermiculture. They also offer a product called The Worm Factory, a system of stackable trays (up to eight) that makes it easy to compost kitchen scraps right in the corner of your own kitchen. What would normally go into the landfill can become food for your plants. It’s a tight, orderly design, so there’s little chance of worms escaping. However, for those who can’t bear the idea of live worms in the house, Good Earth Worms also sells castings in bags, boxes and in bulk.

Any gardener, from the most dedicated grower of all things green to the casual hobbyist would benefit from the use of worm castings. The results are astonishing. And all from the most humble of creatures, the worm.

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