FLORIDA — The ubiquitous earthworm may not offer companionship as a pet, but it provides a benefit as good as gold for a backyard garden — poop.
Vermicomposting, also known as worm farming or composting with worms, uses worms to break down kitchen waste into nutrient-rich fertilizer and soil amendments. Vermicast, also called worm castings or worm manure, is the end product after worms digest and expel organic matter. It contains water-soluble nutrients and is an excellent soil conditioner.
A pound of wriggly worms can turn 65 pounds of food waste into garden compost in 100 days, according to the University of Florida’s Institute of Food and Agricultural Sciences Extension outreach program.
It’s the perfect composting solution in zero-waste efforts, according to UF/IFAS experts.
It’s different than traditional composting, where food and yard waste slowly decompose together in a bin, and won’t attract rats and other vermin, according to Tiare “Tia” Silvasy, an Orange County extension agent II.
She’s an experienced worm farmer still working with the materials she originally purchased 20 years ago.
The first thing in worm farming is the basic setup. A multi-layer bin with a lid is needed. It can be made from an old container or purchased at a garden center.
“I bought mine 20 years ago. It’s UV-resistant. It’s got a lid on top and a spigot at the bottom to collect the worm ‘tea,’” Silvasy said.
Worm tea is produced by rinsing or bathing the worms once a week or so. It too is used as a fertilizer.
If the worm bin is purchased, gardeners can expect about a $100 start-up cost. Commercial bins range from $60 to $130 and worms start at about $20 per pound.
The bottom layer collects the vermicast. Newspaper or other shredded paper provide bedding for the worms and chopped up vegetable, fruit and other organic scraps from the kitchen are placed on top.
Then, the digestive work begins.
Worms chomp on coffee grinds, tea bags, non-citrus fruits, breads, pastas, vegetable scraps and more. When the food is balanced properly with paper, the worm farm will not smell.
“Egg shells can be used as a grit. Worms have gizzards like chickens, to break down food scraps. Any vegetable scrap, just cut them up really small,” Silvasy said. “Worms are fun pets.”
Silvasy cautions against composting too much bread during summer months, as that can draw flies, and says papaya seeds are believed to sterilize the worm population.
Usually red wigglers or tiger worms are the recommended composting worms.
“Once you get into a cycle, you will get compost once a month. They’ll eat all the paper and food scraps, and once it gets down to the bottom bin, you take that and put it in your soil,” Silvasy said. “Some [worms] may die but they also reproduce. They lay cocoons with three eggs that hatch 30 to 90 days later, so it’s a steady population.”
She recommends providing one pound of worms with about a half pound of scraps to eat per day and backing off food if not entirely composted.
“I use [vermicast] for everything. It’s good for building the soil and increasing the soil moisture. It helps for the long term too. The organic compost from the worms lasts a long time,” Silvasy said.
Worms like shade. A covered area not at risk of flooding is an ideal location for a worm farm.
Some people put frozen water bottles in the bin to keep their worms cool.
“It’s like pajamas for dogs,” Silvasy said. “It’s not really needed.”
Lanette Sobel, who owns Fertile Earth Worm Farm in Miami, has been worm farming for about 12 years.
“It’s been an evolution,” she said. “I started out with a bin underneath my kitchen sink and then I started doing presentations.”
Worm farming has increased in popularity during the COVID-19 pandemic as people look for more ways to be self-reliant, she said.
“We also know that 40% of nitrogen-based fertilizers run off directly into nearshore waters. So, anything that is organic is way better for the environment and earthworm castings are the best,” Sobel added.
Both worm farmers recommend washing your hands after touching soil, compost and any other organic material as part of normal hygiene.