Innovative program transforms yard waste into valuable material: 'We're capturing it and we're going to put it to use'

"My tomatoes get so big every year it's ridiculous. I can't eat them all."

That's John Webster, the founder of "Biochar On Site" and a longtime evangelist for the incredible powers of the charcoal-like substance called biochar to supercharge a garden and absorb harmful carbon from the atmosphere.

I first met John a few years ago, when he was selling compost and biochar to local gardeners at our local community garden in Park City, Utah. 

And on a recent weekend in Park City, Webster invited me to check out an innovative program run by a local homeowners association to create biochar out of yard waste, invasive weeds, and tree branches — and while HOAs often get a bad rap for restrictions, this case was a win for residents' gardens and for the planet. 

It's part of the Pinebrook HOA's fire mitigation efforts — encouraging residents to clear dry brush that could go up in flames in this high wildfire-risk neighborhood and replacing it with a substance that is far less flammable and can keep carbon in the landscape for hundreds of years or more. 

Here's how it works. Residents drop off their unwanted yard waste, and it's burned in what they call a flame cap kiln, a simple, portable, affordable tool to transform debris to biochar on site. It looks like a big open burn pile, but this one burns safer, cleaner, and with less harmful emissions and damage to the landscape.

"Effectively what we do is we expose the biomass to high heat in the absence of carbon," Webster tells me. "We're capturing it and we're going to put it to use — this allows you to create a tool out of it. This is an investment in the future. It's multi-generational soil production."

It's actually an ancient technology first engineered in Japan, where farmers used open containers to turn wood and bamboo into the carbon-rich material that improves soil. The kiln limits airflow just enough to turn the biomass into captured biochar instead of ash, a process called flame carbonization.

Once the flame dies down and the pile is reduced to glowing coals, a team of experts water the pile to stop the burn and preserve the carbon — and they're left with what looks just like charcoal, but is so much more. "Seventy-five percent of this chunk will still be in the soil after a thousand years," Webster tells me with enthusiasm. "This is a long-term investment in soil health." 

The primary modern process for creating biochar, known as pyrolysis, produces a black, carbon-rich material that is used to reverse environmental damage in polluted soil, and it can be done without releasing as many greenhouse gases as traditional burning methods.

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Biochar helps crops grow because it improves soil fertility, soil structure, water retention, and drainage, while also adding nutrients to the soil. As a result, biochar reduces the need for chemical fertilizers and pesticides.

Webster's company, Biochar on Site, is working to promote portable, on-site biochar production and use for ecological restoration. They're working with local communities like the one in my neighborhood to "normalize the practice, fostering regenerative land stewardship, mitigating fire risks, and increasing soil carbon for resilient ecosystems."

An estimated 74 million people in the U.S. live in areas governed by a homeowners association — and while The Cool Down regularly covers times when HOAs have prevented homeowners from taking eco-friendly actions such as installing solar panels, they can also be a powerful source for positive local action through programs like this one. (TCD put together a guide to working with your HOA, which you can find here.)

Alan Spadafora, the founder of Circle Soil, is also on site helping to create the biochar — and he's actually created a potting soil available for purchase that combines biochar with high-quality, locally sourced ingredients to create a peat-free potting mix that's good for plants, and better for the planet. 

Spadafora told me he created the product after working in the forestry industry and seeing massive green waste from cleared trees and brush getting burned or sent to the landfill, where it would turn into methane gas, a powerful, dangerous greenhouse gas. 

"For me, Circle Soil isn't just about great soil — it's about honoring a centuries-old method of using fire to heal the land," Spadafora says on his website. "Biochar connects us to something timeless, and I believe it's one of the most powerful tools we have to grow both plants and climate solutions."  

And back to his tomato plants, Webster says there's nothing like the power of biochar. 

"It's so great for your garden," he explains. "I like to crunch mine up a little bit and combine it with compost."

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