Red wiggler worms are used for vermicomposting to repurpose and dispose of food waste in a sustainable way. Photo taken at the Arizona Worm Farm in Phoenix on Feb. 1, 2023.
Vv Acevedo reaches into one of the dirt piles that line the Arizona Worm Farm and pulls out a handful of dirt. It’s full of squirming worms buried just beneath the surface.
Located near South Mountain, the farm breeds red wiggler worms for vermicomposting, which is the process of using worms to break down food waste into nutrient-rich soil that fertilizes plants.
“As your plants are growing, they’re putting all of that energy and nutrients into the leaves and the fruit and everything that falls,” said Acevedo, director of education at the farm. “It doesn’t have a way of returning back into the soil. That’s where the worms come in. They will help break all that down and return those nutrients into the soil.”
The farm is working to combat food waste with its vermicomposting efforts, selling worms to promote commercial and backyard vermicomposting, and educating consumers and businesses about the process.
Food waste is any food that gets thrown away, wastes resources, adds to landfills, and increases environmental impact through methane gas production.
The U.S. Department of Agriculture’s website defines food waste as “the edible amount of food, postharvest, that is available for human consumption but is not consumed for any reason.”
Food waste is a huge problem. Each year, 119 billion pounds of food is wasted in the U.S. with nearly 40% of all food in America wasted, according to Feeding America, a nonprofit that addresses hunger.
The Arizona Worm Farm started in 2017 and is halfway through a 10-year plan to create a self-sustaining, zero-waste environment with a focus on vermicomposting. The farm works with a number of businesses to collect food waste and dispose of it in a more sustainable way.
“We get green waste from salad producers that don’t put them in those bags that go in your grocery store, we get horse manure from carefully curated stables, and we get ground landscape waste from the city of Phoenix from a landfill diversion program,” said Zach Brooks, owner of the Arizona Worm Farm. “If we bury it (garbage) in a hole, we don’t make use of that. If we take it and capture that resource … we can continue to use that resource to feed ourselves.”
While vermicomposting recaptures nutrients from food waste and uses them to grow new plants, the process also recaptures water in the food that allows it to grow. That is especially important in Arizona during a megadrought.
The Arizona Worm Farm uses a no-till method, meaning no chemicals, herbicides, pesticides or commercial fertilizer can be used. The farm uses only worm castings – or excrement – which produce microbial activity.
“Those microbes convert what’s in the compost into what the plants need at the exact time that the plants need it,” Brooks said.
The farm receives 320 cubic yards of food waste from partners each week. Workers layer that in a custom mix, wet it, turn it, and monitor it for six months until it is ready to sell to businesses and backyard gardens.
Businesses can enroll in programs that pick up their food waste and have it taken to a composting facility, like the worm farm, instead of throwing it in with other waste and paying to have it hauled to a landfill.
Individuals have a few options to participate in vermicomposting and repurposing their food waste. They can start bin-sized operations where they throw food scraps in with worms and let the wrigglers do their job.
“Our main goal is to get more people backyard gardening, more people using natural things in their garden as an alternative to chemical fertilizers,” said Sarah Spainhower, head worm breeder at the farm.
Another option for backyard gardeners is to take their food waste and worms and add them directly to their garden. The worms digest the food waste and produce castings, which provide nutrients to the garden. The castings cultivate slower, healthier organic growth and lead to more delicious fruits and vegetables, according to Brooks.
Vermicomposting can take place in a raised bed or garden. People can add fruits, vegetables or leftover food and cover that with an inch of fallen leaves and water, and the worms will take care of the rest.
“Compost, worms, and castings operate at the root level. So they’re feeding your plants without doing anything to burn your plants,” Brooks said. “They won’t over-fertilize them, and they don’t pollute our waterways.”
Why worms?
Brooks’ original idea for the farm was to raise chickens, but he couldn’t breed worms fast enough to feed the hens, as they devoured hundreds at feeding time. In the process, he found out how good worms are for soil.
“When we saw how great worms were in the gardens and what they could do, we decided that we needed to make those worms available to everybody in Phoenix and beyond,” Brooks said.
The Arizona Worm Farm breeds and grows 80,000 worms a week and touts itself as one of the largest producers of worms in the United States. Spainhower said the process of getting the worms ready to sell takes about three months. They put about 600 worms in each breeding tray, which can result in 6,000 to 8,000 worms. In the busy spring season, the farm can easily sell 60,000 worms a week, she said.
Interest in composting has been growing
A report from the Environmental Protection Agency showed an increase in composting efforts from 1960 to 2019 with 680,000 tons composted in 1960 and 3.3 million tons in 2019.
The report also broke down the distribution of 66 million tons of waste generated across three categories in 2019: food retail, food service, and households. Of that, 39.6 million tons ended up in landfills, 5 million tons were donated to food banks and 3.3 million tons went to composting.
Michigan State University expanded a vermicomposting effort to 1 million red wiggler worms and is seeing success in reducing the university’s food waste.
The effort was originally a research project by now-retired horticulture professor John Biernbaum and has grown from about 20,000 pounds of food composted a year to 140,000 pounds in 2021.
High-cost limits participants
But vermicomposting comes with costs.
Brooks said it costs about $44 per ton for a business to have its garbage picked up and taken to a landfill.
“To bring it here and sustainably process it is $100 a ton,” he said. ”So you can say, ‘That’s two and a half times as much money,’ or you can say, ‘I’m spending $400 a month now. It would cost me $1,000 a month. I can afford that $600 to make sure that we are taking care of our garbage.’”
The Arizona Worm Farm uses plastic bags to package its compost. Brooks said he would prefer to use compostable coffee bags, but said they are 10 times more expensive than plastic.
“It’s hard for a company my size to do that, but ultimately we need companies that can afford to do it,” Brooks said.
Another limitation for composting on a larger scale is separating everything that is not compostable. San Francisco, for example, has a mandatory recycling and composting ordinance, which requires residents and businesses to separate recyclables and compostables from waste that goes to landfills. Arizona does not have a similar ordinance, though some people use composting services or compost at home.
The combination of vermicomposting and thermophilic composting – the process of letting bacteria break down food waste – can process every bit of food and landscape waste that a family produces, according to Brooks.
“You can do that in an apartment and you can do that in a dorm,” Brooks said. “Now, is it going to fit nicely in your designer kitchen? Maybe not, so are there practical limits to it? Probably. Could most of us do it? Absolutely.”
Brooks said people may believe it’s easier to throw food away than to compost.
“As much work as it is to package your garbage and put it in the garbage and take it out to the curb to be picked up, it’s less work to feed your worms,” Brooks said.
In Phoenix, the farm has taught more than 4,640 people to compost and garden, he said. However, with 5 million people in the Phoenix metropolitan area, Brooks said the farm has a long way to go.
On its website, the farm has posted videos about its methods and processes that have been viewed by more than 700,000 people worldwide. The farm also has hosted conferences on worm management for farmers.
Beyond vermicomposting
Waste Not, a Scottsdale company that combats food waste, has partnered with the Arizona Worm Farm in the past. The nonprofit specializes in food rescue, diverting food that would otherwise be wasted to people in need. Last year, the organization rescued 2.4 million pounds of food and conserved more than 220 million gallons of water, executive director Hillary Bryant said.
A 2021 report on United States food loss and waste from the EPA concluded that simply recycling and composting aren’t enough; there needs to be a reduction in waste.
The EPA food recovery hierarchy, used by Waste Not, recommends reducing the overproduction of food as the main way to combat food waste, followed by feeding people in need, feeding animals, industrial uses, and composting. Sending food waste to landfills is a last resort.
Arizona has one of the highest shares of food waste in the U.S., according to Bryant and an analysis by lawn-care company LawnStarter.
Bryant said collaboration between local organizations that tackle different parts of the food system – like the Arizona Worm Farm – is essential.
“It’s really important to make those connections and to make sure that food is being used in some way and not just ending up in the landfill, so there are lots of collaborations that we are actively trying to make,” Bryant said. “Making sure that all of these people in the food system, all these companies talk to each other is very important because if we can’t use it, I know someone else can.”
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