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No Worms Wasted

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Vermicomposting flourishes in the Great Lakes region

By Carol Thompson
Spring 2011
It’s a bleak 19-degree February morning outside the translucent walls of the hoop house, but inside the worm bed where Michigan State University Student Organic Farm employee Brendan Sinclair sticks his hands, it’s a balmy 50 degrees.
The hoop house, affectionately named Compost Commons, accommodates the Student Organic Farm’s compost and vermicompost operations. It’s where Sinclair and other employees and farm volunteers are working on a composting model that transforms food waste into a rich, organic fertilizer with the help of some dedicated decomposers.
Vermicomposting refers to the breaking down of food and plant material using worms, typically a species called “red wiggler.”
Castings, a more respectable term for the worm waste, are even higher in nutrients than traditional compost, says Kelly Trace, development coordinator for a Milwaukee-based urban farm called Growing Power.
Finished vermicompost is made of castings mixed with decomposed organic matter and has higher levels of plant nutrients and more microbes than traditional compost because of the microbes present in the worms’ digestive systems.
Castings can also be mixed into soil, layered on top of soil or made into compost tea. Compost tea is a mixture of castings and water that can be sprayed on plants as a natural pesticide and insecticide.
Growing Power says vermicomposting:
• improves soil’s physical structure
• improves soil’s water holding capability
• adds microorganisms to soil
• attracts more earthworms
• improves root growth
• enhances crop yield
Vermicomposting and traditional composting are important aspects of Growing Power’s vision to get healthy food to urban areas where residents frequently don’t have access to fresh foods or grocery stores.
“To grow really healthy food you need to have healthy soil,” Trace says. Because soil is frequently contaminated in urban settings, having fresh compost is vital for Growing Power’s operations.
Regenerating food waste into castings and compost doesn’t only create rich, healthy soil and natural pesticides, but it also keeps food waste from getting dumped in landfills.
In 2009, Americans generated 243 million tons of waste, and only recycled or composted 33.8 percent of it, according to the U.S. Environmental Protection Agency.
That means Americans dumped into landfills household waste weighing more than 44 million African elephants. And that figure doesn’t even include industrial, hazardous or construction waste; it’s just everyday items like plastic wrap, old receipts and food scraps, from homes, hospitals, schools and businesses.
But some of that waste is more dangerous to landfills than the rest. Food scraps, which accounted for 14.1 percent of municipal waste in 2009, weighed in at 34.29 million tons, according to the EPA. This moist, heavy, organic food waste causes leaching in older landfills built without plastic liners and drainage systems, says Cornell Food Science professor Joe Regenstein.
Food waste also emits methane, a greenhouse gas more effective at trapping heat than carbon dioxide. And although some landfills harvest methane for fuel, it’s not an efficient fuel-extraction process compared to biodigesters, which convert organic waste into fertilizers and the methane emitted into heat or electrical energy.
Composting or vermicomposting food waste is a better return on investment in a global, holistic sense than harvesting methane, Regenstein says. It would be even better if more of the appropriate food scraps went back into the feeding system for animals.
“[We should] use the food as food value,” Regenstein says. “Which vermicomposting essentially is, except it’s an animal we don’t eat.”
In the past 20 years, Regenstein has seen more schools, restaurants and supermarkets composting and more municipalities keeping organic material out of landfills due to increasingly costly regulations. Diverting waste has become an economic incentive.
“There is clearly an acceleration in composting,” Regenstein says. “I know some places do vermicomposting on a very large scale. In most cases it’s been families dedicated to doing it in their homes.”
Outside of domestic vermicomposting a few companies have picked up the trade. Among them is Morgan Composting in Sears, Mich., which has more than five million worms.
Jeremie Morgan, who runs the vermicomposting operation at Morgan Composting, came back to work full-time at the family company two years ago. The company produces more than two semi-truck loads of castings every year. Those castings are sold in potting soil to individual costumers in small volumes and more than 30 retail outlets from Michigan to Pennsylvania on a large scale.
The interest in vermicomposting is growing in the Midwest, but people are still uneducated about the process, Morgan says. He attended a meeting in Wisconsin about small gardens and greenhouses with his wife where they discussed vermicomposting. In classes and meetings like these, Morgan and his wife frequently end up helping the teachers with the vermicomposting material.
“The biggest thing is that people are uneducated,” Morgan says. “It’s slow coming, but it’s coming.”
The Worm Team at MSU is working on the education front. By studying how worms react to different foods and environments, the team can develop the best vermicomposting model and put it into practice at the Student Organic Farm.
Twice a week, Sinclair picks up about 250 pounds of food waste from two of Michigan State’s dining halls. He collects waste generated in the kitchens like eggshells and old produce, not food scraps that diners leave on their dishes. Back at Compost Commons, the waste is allowed to break down and added to the outside end of the worm bed. The worms move toward the fresh food, leaving their castings behind for harvest.
The worm bed stays warm, even in the dead of Michigan winters, because it’s located under a tented plastic cover inside a passive solar greenhouse. Also under the plastic cover is a separate compost pile that can heat up to 150 degrees to provide additional heat.
A red wiggler worm can eat between 50 and 100 percent of its body weight per day. In one semester — 15 weeks — the worms on the Student Organic Farm went through almost two tons of waste.
In an ideal environment worms can double in 60 days, which Sinclair has seen quite literally first hand. He even played worm midwife when he happened to pick up a handful of worms as some were hatching.
“I got to see some baby worms wiggle out of a mature cocoon right in my palm,” Sinclair says. “It was awesome.”
Worms are hermaphrodites and can reproduce after they’re a month old and develop a clitellum, the thick white band around their bodies that holds genetic material. After mating, the clitellum slides down the worm’s body collecting eggs and sperm and a cocoon forms, holding four to six baby worms.
As the Student Organic Farm’s worm population continues to increase, so will its capacity to break down food waste. The Worm Team’s goal is to use finished vermicompost material for transplanting media and soil amendments for the Student Organic Farm, though some may be used for research.
“I don’t think that we would have any trouble selling the vermicompost in the future if we wanted to, but being able to produce our own sources of fertility at the Student Organic Farm is a valuable resource,” Sinclair says. “I hope that most of it would stay on the farm.”
Carol Thompson is a junior studying environmental journalism at MSU. Contact her at thomp872@msu.edu.
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