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New Mexico State University

New Mexico State University

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Composting is for the Worms

LAS CRUCES -- Preparing large holiday meals produces more than happy families with full tummies. It also produces wastes -- peelings, shreddings and choppings -- that make excellent worm feed.


"It's tempting to stuff all your food waste down the garbage disposal," said George Dickerson, horticulture specialist with New Mexico State University's Cooperative Extension Service. "One alternative is to turn those wastes over to a herd of worms. Red worms or red wigglers will make short work of your leftover banana peels and apple cores, turning them into rich compost that can be used in your garden next spring."

Vermicomposting, or composting with earthworms, can be done in the garage or even under the kitchen sink. "Worm bins located near a hot water heater will save trips outside in the cold carrying food wastes to the backyard compost bin," he said. The hot water heater will keep the worms warm, ensuring an optimum recycling environment.

"Keeping the worms in their bin is important if you don't want a mess in your garage," Dickerson said. Since red wigglers tend to be surface feeders, bins should be no more than 8 to 12 inches deep. The length and width of the bin will depend on the amount of food wastes your family produces each week. "A good rule of thumb is to provide one square foot of surface area per pound of waste in your bin."

Plastic bins with one-quarter inch holes in the bottom will provide good drainage and are less messy than wooden bins. Place bin lids underneath, supporting the bins on top with wooden slats. The liquid that catches in the lids can be used as fertilizer in flower beds.

"Bedding for worm compost bins can be made from shredded newspaper, cardboard, leaves, straw or peat moss," Dickerson said. "Keep the bedding moist, but not water-logged. Throw in a handful of sand to provide grit for the worms' digestive systems."

Under optimum conditions, red worms or wigglers can eat their own weight in food scraps and bedding in one day. On average, it takes 2 pounds of earthworms to recycle a pound of food waste in 24 hours.

Composting worms can be purchased through many garden publications. When the worms arrive, add them to the top of the moist bedding. They will disappear into the bedding within a few minutes. Cover the top of the bin with a moist burlap bag or straw to prevent the bedding from drying out.

"Wigglers will eat all kinds of food wastes, including coffee grounds, tea bags, vegetable and fruit wastes, and even pulverized egg shells," Dickerson said. Bury food wastes in the bedding instead of adding them to the top.

Scraps can be added continually to the bin for two to three months until the bedding disappears. "It's then time to harvest the worms and compost," he said.

To remove worms from the finished compost, place the compost in small piles on a tarp in the sun. Red worms don't like light, so they'll move to the bottoms of the piles. Scrape the top layer of compost off each pile until you reach the worms. Combine piles and repeat the process until you have a pile of finished compost and a pile of worms.

"Use the worms to start a new bin and store the compost for use in next year's flower or vegetable garden," Dickerson said.