Joseph Walker says he’s killed his weight in worms.

But after a dozen tries, Walker believes he’s come up with an effective process for encouraging worms to eat — and more important, to poop — and then converting their teeny droppings into an organic fertilizer.

The Brigham Young University student’s main customers are commercial growers of marijuana, a market that’s exploding as more states approve pot use for medicinal or recreational purposes.

“This market alone purchases most of my existing product,” said Walker, 22, originally from Eugene, Ore. and now studying landscape management and entrepreneurship at BYU.

The startup company he established, OmniEarth, has earned accolades in three student entrepreneurship competitions this year for its use of worm castings — the technical term for nightcrawler droppings — as a completely natural product for fertilizing all sorts of plants.

While Walker insists his product works well in lawns and gardens, his business plan is focused on marijuana growers.

He became interested in fertilizer while doing landscaping work between the end of his mission in Salt Lake City for The Church of Jesus Christ of Latter-day Saints and his return to BYU.

Taking care of dozens of yards, Walker realized his employer used a lot of chemical fertilizers.

“It didn’t bug me, but over time a lot of people wouldn’t hire us because of the artificial fertilizers,” he said. “I wondered if I could find an organic solution.”

Walker turned for general business advice to his grandfather, an entrepreneur in his own right.

“He had an idea he thought I should pursue,” Walker recalled. “He said worm poop. At first, I’ll be honest, I thought he was crazy. It sounded like a ridiculous idea. But after just five hours of research, I understood this could be a really cool organic solution for any industry, not just lawn care.”

(Steve Griffin | The Salt Lake Tribune) Brigham Young University student Joseph Walker was named the Utah winner of the 2017 regional competition for the Global Student Entrepreneur Awards (GSEA) for his organic fertilizer company, OmniEarth, based out of Provo. His fertilizer, made from worm droppings, optimizes the growth and potency of marijuana plants for certified growers, he said.

And the more research he did — he says he’s invested more than 4,000 hours — the more apparent it became that marijuana cultivation was the business to be in. Walker read a Bloomberg News report that said the marijuana market is expected to grow 600 percent in the next decade. Forbes magazine called it the fastest growing industry in America.

He identified a half-dozen companies that were selling worm castings and called them, seeking information about what kind of worms they used and who bought their finished product.

“They all said it’s the marijuana market,” he said. “There is a seemingly insatiable need. None of the companies said they could keep up with current orders. There’s this huge need to go green.”

That’s true, said Bethany Gomez, director of research for Brightfield Group, a Chicago-based market research firm that focuses on cannabis issues.

Using organic, pesticide-free, innovative and sustainable products like worm castings, she said, “is a way for cannabis growers to differentiate themselves and be eco-friendly, which is very important to a significant portion of cannabis consumers. They’re overwhelmingly demanding about their cannabis being organic, especially with higher-end products and things like edibles and concentrates.”

Walker started putting his business together, finding a small warehouse space where he could stack soil-filled crates of worms. While many of his competitors use red wiggler worms, Walker preferred African worms because they eat more.

Over a number of months, he worked to figure what compost to feed the worms so they’ll eat like crazy and relieve themselves more often. He tinkered with temperatures and humidities and the water content of the soil, zeroing on the right combination to maximize production.

“It wasn’t easy,” he admitted. “I’m on my twelfth formula now.”

His research was aided by cash prizes he picked up in contests.

In January, OmniEarth got a $900 grant from the University of Utah’s Lassonde Entrepreneur Institute through its “Get Seeded” program, which helps student startups get to the next milestone of their development.

(Steve Griffin | The Salt Lake Tribune) Brigham Young University student Joseph Walker was named the Utah winner of the 2017 regional competition for the Global Student Entrepreneur Awards (GSEA) for his organic fertilizer company, OmniEarth, based out of Provo. A sample is pictured here. His fertilizer optimizes the growth and potency of marijuana plants for certified growers, he said.

Two months later, Walker hit it big. OmniEarth was one of eight finalists in the New Venture Challenge, a competition sponsored by the Rollins Center for Entrepreneurship and Technology at BYU. He didn’t win, but he got $15,000.

And then in November at Utah Valley University, OmniEarth won the Provo regional competition for the international Global Student Entrepreneur Awards, whose winner will get a $50,000 prize next April in Toronto.

Walker knows that his product’s marijuana connection might be an “eyecatcher” for judges, but he prefers to think the positive reception to OmniEarth is based on “this product satisfying so many businesses — greenhouses, lawn care, gardening. There are so many different avenues.”

He’s sold about 500 pounds of his product to his former boss, Gary Tidwell of GT Lawn Renovation Inc. in Layton. Tidwell applied it to a 30-acre parcel of land he knows well from 20 years of ownership. He’s convinced that “it has absolutely changed the areas where I’m using it, 180 degrees for the better. I have no idea how it really works with the science and all, but you can see it’s better.”

Dan Ramsay says Walker will face challenges scaling up his business to make it profitable.

Ramsay is the general manager of Natural Order Supply, a company in Grand Junction, Colo., that supplies equipment and organic fertilizers to farmers, gardeners and commercial marijuana growers.

“It’s neat to see college kids doing research,” he said. “Organic trends are common in the cannabis industry and something I promote with my business.”

There’s a lot of competition, Ramsay said, but he added, “the industry will continue to expand, and as it expands, there will continue to be a need for more organic fertilizers.”

Walker’s counting on it, saying he’s invested “every penny” of his contest winnings into fine-tuning his product and expanding his operations to meet the anticipated demand.

And while Walker said he does not consume marijuana himself, he’s clear on one point: “I sure hope Utah legalizes medical marijuana.”