Vermicompost: Breaking Down The Benefits
Are there advantages to applying worm castings as a fertilizer to your crop? Mark Elzinga says yes.
June 15, 2011
Mark Elzinga began researching worm compost four years ago. As owner of Elzinga & Hoeksema Greenhouses (E&H) in Portage and Kalamazoo, Mich., he was in the midst of revamping his facility and looking for more sustainable ways to cut the facility's energy costs and reliance on synthetic fertilizers and pesticides
"I'm not a tree hugger," says Elzinga, who oversees 1.4 million square feet of greenhouses. "I went into organics for the money."
Elzinga says it was around then that he discovered Worm Power, a vermicompost company based in Upstate New York that recently partnered with Harris Seeds to distribute its products. He ordered a few samples and then more. He's now a fan, mixing up powerful tea - or vermi-espresso, as he likes to call it - which uses 10 percent vermicompost to water by volume. Elzinga touts the tea as the secret to keeping his organic plants growing strong. The mix is a combination of droppings from red worms mixed with molasses, sea kelp and other organics. Together, those ingredients create a bacteria-rich liquid that, Elzinga says, outperforms commercial fertilizers.
Elzinga applies his vermicompost to E&H's Fresh Flavors branded organic vegetable and herb potted plants, as well as his ornamental crops. He even mixes vermicompost into a proprietary organic soil mix that's sold under the Fresh Flavors brand at Meijer, a large Midwest supermarket chain. "We don't use fertilizer," Elzinga says. "We use a biological amendment."
Research has established that worm compost, when added as a soil amendment, increases soil fertility, improves plant nutrient uptake, enhances soil structure and boosts soil's water-holding capacity.
There are other benefits, as well. If you put a slide sample of E&H's compost tea under a microscope, Elzinga says you can see 100,000 beneficial bacteria with 90 percent fungal density and 400 nematodes. The added benefit is the nematodes can eat the larvae of common greenhouse pests like shore flies and gnats.
"It stops pythium in snapdragons," Elzinga says. "I can say that because I've seen it."
For the last few years, worm-composting companies around the country have begun research in the pest and disease areas. Studies show vermicompost can protect plants from a variety of pathogens. Researchers are working to uncover the details of how this works. Worm Power, for example, has been the subject of a five-year university laboratory study, which shows it to be effective in suppressing pythium in cucumber seedlings.
The vermicompost market has taken off the last few years with sales of home worm-composting bins and worm poop from bait dealers. Elzinga, however, believes that while straight worm poop from a bait dealer might be OK to spread in a field, he needs a product of consistent quality for a greenhouse. You don't know what a bait dealer's worms have been fed, Elzinga says.
For example, at Worm Power, cow manure from a single dairy farm is combined with silage and composted at high temperatures before it undergoes the worm composting process. Every step of the process is controlled and tested. "The techniques they use are so important," Elzinga says. "Their facility is Club Med for worms."
Since starting his work with compost tea, Elzinga says he has been able to drive down costs considerably. He is now able to pre-activate some of the vermicompost material, a process that increases the amount of fungal biomass in compost before it is brewed into tea. E&H's cost to make compost tea has dropped to $115 a week from $1,700 a week when it started. "Vermicompost is the base for everything we do," Elzinga says.
Patricia Riedman Yeager is a Chicago-based freelance writer and editor. She can be reached at firstname.lastname@example.org.