June/July 2012 California Bountiful magazine
Story by Trina Wood
Photos by Trina Wood and Matt Salvo
Gardeners use nature's decomposers to turn kitchen scraps into black gold
Martha Teeter gets a little help checking on the worms in her composting box from neighbor Wren Chew, in pink shirt.
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As an avid gardener, Martha Teeter knew the benefits of composting her kitchen scraps. But it wasn't until her brother started raving about the book "Worms Eat My Garbage" 14 years ago that she realized her compost could deliver more nutrients to her fruits and vegetables with a little help from some wiggly invertebrates. So began Teeter's forays into vermiculture, or worm composting.
"Worm compost (in contrast to garden compost) is more like fertilizer than a medium for enriching plants," Teeter explained. "It also provides micronutrients for plants that are absent from inorganic fertilizers."
While earthworms also enrich and aerate soil, red wigglers, or Eisenia fetida, are the species used for composting. As opposed to earthworms that deposit castings (worm droppings) on top of the soil, red wigglers deposit castings below the surface, at the root of the plant where necessary nutrients such as nitrogen, phosphorus, calcium, magnesium and potassium can be more readily absorbed.
Gardeners who practice vermiculture raise worms in homemade or commercially available bins, in the garage or under the kitchen sink. The worm castings, which look like really dark, fine soil, are harvested and applied as fertilizer to grass, trees, fruits and vegetables.
Tahna Chew joins Wren in the neighborhood's community garden where Teeter grows vegetables.
Using the right system for where you live is the key to success, as Teeter discovered. When she first started worm composting in Massachusetts, she kept her red wigglers in a vertical rotating drum composter in the garage during the winter and would drag it into the driveway in the summer.
Big sister Tahna.
"That was a near-perfect system," said Teeter, who now lives in Yolo County. "But my first bin in California was a dismal failure. It was an open crate, darkened with landscape cloth and kept in the workshop outside. The worms just left the bin through the large holes and never came back."
Worm farmer John Stewart scoops up a pile of red wigglers and castings.
Through a little trial and error, Teeter figured out how to keep her worms content and her garden thriving. She now uses a few different systems, including in-ground composting in the large community garden area outside her front door. By digging a hole about a foot deep and burying appropriate food waste, worms are attracted to her raised beds. This method works well in the fall and winter to enrich the soil where the plants aren't growing, Teeter said. By spring, the soil is nutrient-rich and helps her new plants flourish.
According to John Stewart, who co-owns The Worm Farm in Butte County, worms need food, moisture and the right temperature (65 to 75 degrees).
"If you keep those right, the worms will be happy and stay," said Stewart, who runs the farm with his parents Arlita and Mark Purser.
While there are many commercial worm-growing businesses in the country, The Worm Farm is one of the largest, with 15 of its 40 acres devoted to worms—10 of those acres are covered in rows nearly 3 feet high and 8 feet wide where about a pound of worms lives in every linear foot. Customers can purchase worms, castings or choose from among dozens of custom mixes depending on their soil or crop requirements.
Irrigation hoses keep the worm rows moist.
Stewart never imagined that "worm farmer" would make it to his resume. But after working as a computer programmer in Simi Valley for two decades, he was ready for a change and moved to Durham, where his parents had founded The Worm Farm in 1990. The property has been in the family for more than 100 years and once was home to a chicken farm run by Arlita's father.
"He was getting older and less able to do the work, so he gave up the chickens, but then he went stir-crazy," Arlita Purser recalled. "So when we saw a sign on the side of the freeway (on a trip to visit him) that read 'Earthworm growers wanted,' we said, 'Hmmm, that's very unusual,' and we drove out of our way to check it out. We decided this was something he could do."
The worms are separated from their castings with the help of specialized equipment.
They bought 25 pounds of worms on the spot and carted them up to Durham—in the middle of winter. They quickly learned that raising worms wasn't as simple as they first thought.
"They all died, because we didn't know what the heck we were doing," Purser said. "So then we started doing more research and replenished our supply and started doing it properly."
They also started a non-profit called The Worm Farm Learning Foundation in 2008 and offer tours to schoolchildren and groups, teaching them about caring for the earth and the benefits of worm composting.
The castings, which are packaged as soil amendment, and the worms help gardeners and farmers grow healthy crops.
"That's the favorite part of my day, seeing the big yellow school buses drive up and hearing the kids playing on the big piles of compost—they just love it," Purser said.
Teeter is also passionate about sharing her knowledge of worm composting and recently helped record a video with the city of Davis on worm and in-ground composting.
"I'm a passionate reuse/recycle person," she said. "I love to recruit new advocates."
Under optimal conditions, a pound of red wigglers can consume up to a pound of kitchen scraps a day.