The Scoop on Poop: Bug Waste

Could insects—and their waste— provide a possible solution to regenerating healthy soil? A recent article from the BBC reports that over 33% of the world’s soil is currently degraded, “depleted of the nutrients necessary for healthy plant growth,” yet hope lies in a bug that can eat four times its own weight in organic waste and quickly turn it into sustainable fertilizer.

Using black soldier fly larvae (BSFL) to create fertilizer happens in a fraction of the time it takes for traditional composting and results in a 2-2-2 fertilizer rich in microbial activity. The excrement of BSFL, or frass, has such promising potential that the USDA has awarded grants to three BSFL projects in May of last year, as part of the Fertilizer Production Expansion Program (FPEP).

A $4 million grant went to Chapul Farms, which designs, builds, and operates insect farms that convert organic waste into high protein animal feed and fertilizer. “It was really the war in Ukraine that stopped the shipment of fertilizer and made the U.S. realize that our dependency on outside fertilizer made us vulnerable as a nation,” said Chapul Farm COO Todd Severson. “And that’s when they put a lot of money in fertilizer production in the U.S.”

Chapul works with neighboring farms to exchange waste for frass, creating a circular system for farming. But it’s also creating a better overall ecosystem—the frass provides essential nutrients to plants and fosters more biodiverse soil, encouraging the growth of native plants and repopulating insect species.

Mimi Casteel, an Oregon wine farmer using Chapul’s frass, told the BBC, “We could make compost out of anything but the impact of running it through this insect biology has all of these [positive] implications. It’s exciting for so many reasons: it’s a portable, pretty low cost investment compared to some other things that we’re considering as part of dealing with our massive problems with waste, and soldier flies are replacing a missing layer of diversity.”

Unlike chemical fertilizers, which can deplete soil progressively and make it dependent on further inputs, the microbes in frass proliferate over time, rebuilding soil health. Eventually, it takes less frass to maintain the same levels of soil productivity.

“Finding a use for this is important, but if you’re going to market frass as a fertilizer, you need to regulate it, which takes time,” Shankar Ganapathi Shanmugam told the BBC. Shanmugam, an Assistant Research Professor in the Department of Plant and Soil Sciences at Mississippi State University, is spearheading U.S. research on frass as a crop nutrient. “And to make these regulations you need research.”

The FPEP funds mentioned above will support construction and equipment for BSFL facilities in Oregon and North Dakota, with an anticipated yield of 10,000 tons of frass per location per year and generating 59 new jobs upon its completion in 2026.