- Author: Deborah Stevens
My worm hobby began in 1999 after I attended a Master Gardener composting class. This hobby continues to fascinate me. Worms recycle my kitchen garbage, and I’m still amazed by the process.
Two years ago I went to North Carolina State University’s annual vermiculture conference. The conference was so inspiring that I went again last year. It is the only conference about earthworm farming and mid- to large-scale vermicomposting in North America.
The conference, coordinated by a university extension specialist, offers science-based information. One of the topics was the difference between vermicompost tea and leachate.
Both begin with red wigglers, which are small earthworms that live near the top of the soil and consume organic matter. I feed my worms kitchen garbage and disease-free plant debris from my yard. My goal is to create vermicompost and aerated compost tea for nourishing a healthy, chemical-free garden.
To make aerated compost tea, you need a 12- to 24-hour aeration cycle, de-cholorinated water and finished compost. Alternatively, you can make the tea in a bucket in three to seven days by stirring occasionally.
By introducing air, you encourage the proliferation of aerobic microorganisms and discourage the anaerobic microorganisms that may produce byproducts unfavorable to plant growth.
Vermicompost tea contains a large diversity of bacteria, fungi, protozoa and nematodes. These microorganisms increase soil biological activity, encourage plant vigor, yield, bud break, fruiting, flowering, color, root volume, seed germination, and pest and disease resistance. You can use vermicompost as a foliar spray or soil drench.
Many worm composters are unfamiliar with the topic of aerated compost tea, preferring to use the leachate that many vermicompost systems encourage. Although leachate seems to benefit plants, it comes with some risk.
Research suggests that the use of leachate should be discouraged. Vermicompost is not leachate. The excess water that drips through a worm bin is leachate. It picks up undigested material which may contain pathogens and chemicals toxic to plants and humans.
A properly maintained worm bin will not collect or seep excess water or leachate.
Use leachate to water a favorite weed, or flush leachate down the toilet. Using leachate on plants, especially edibles, is not worth the risk of pathogenic contamination.
As for the vermicompost produced by red wigglers in the worm bin, the worms and microbes gobble up the pathogens in their environment and do not release the pathogens back into the soil.
Microbes are part of a worm-bin ecosystem. They live and work amongst the worms in the vermicompost, eating and overpopulating the pathogens while being ingested by the worms.
The vermicompost is ready to use when you don’t recognize the original feed stock. It should smell clean and earthy and appear brown and crumbly.
I wondered if the pathogens the worms previously digested are freed upon their death. Otto D. Simmons III, a professor of biological and agricultural engineering at North Carolina State University, says that “live worms digest the dead ones and the pathogens are eaten by the surviving worms.”
So why use aerated compost tea? Because it adds organic life to the soil, improves soil structure, water retention, root depth and growth.
A foliar spray of vermicompost tea protects plants from pests and diseases, thus reducing the need for chemicals. I love the idea that my plants seem happier and stronger due to my kitchen waste.
Be sure to use non-chlorinated water when making tea or watering your worm bins. City dwellers can set a jug or bucket of water out for 24 hours to de-gas the chlorine. Rain water collected in buckets is a good alternative.
Workshop: Napa County Master Gardeners will present a workshop on “Fruit Tree Pruning” on Saturday, February 9, at the University of California Cooperative Extension (address below). The morning session (from 9:30 a.m. to 11:30 a.m.) will consist of an indoor lecture. The afternoon session (from 12:30 p.m. to 2:30 p.m.) will consist of a hands-on workshop outdoors in an orchard. You will learn techniques to keep your fruit trees healthy and productive. Online registration (credit card only); Mail in registration (cash or check only).
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. Napa County Master Gardeners (http://cenapa.ucdavis.edu) are available to answer gardening questions in person or by phone, Monday, Wednesday and Friday, 9 a.m. to Noon, at the U. C. Cooperative Extension office, 1710 Soscol Avenue, Suite 4, Napa, 707-253-4221, or from outside City of Napa toll-free at 877-279-3065. Or e-mail your garden questions by following the guidelines on our web site. Click on Napa, then on Have Garden Questions?