Updated April 28.
A dozen Vineyarders spent Earth Day morning at a private home in Edgartown, gathered around a big metal box with flames leaping out. They kept a safe distance from the heat while two experts, in face shields and flame-resistant Nomex clothing, fed yard waste into the dumpster-looking contraption and stomped out any embers that escaped.
On an Island where sourcing gardening and farming supplies can be costly, and where eco-conscious citizens are wary of fertilizer for its impacts on pond habitats, the crowd had come to learn about the hype behind an emerging alternative.
It’s called biochar.
Maggie Craig, a second-year M.V. Vision Fellow working with the Martha’s Vineyard Commission, is collaborating with Island farms and officials to spread the word and best practices, and hopes to get more and more home gardeners on board. With a kiln designed by Dr. Ken Carloni, an ecosystem management consultant and retired university professor who also led the presentation, Craig is producing the material in order to maintain and restore fertile soil without the drawbacks of conventional methods.
Biochar is a charcoal made from heating plant matter in low-oxygen conditions. Even a small amount has a vast surface area due to the cellular structure of plant matter. This lets it hold large amounts of water, nutrients, and beneficial microbes when combined with compost and added to soil. Since it keeps nutrients like nitrogen and phosphorus in the ground where they belong, it can serve as a substitute for fertilizer. “A gram of our biochar has a surface area slightly smaller than a tennis court,” Dr. Carloni said on Tuesday.
Finding biomass for the kiln is also an opportunity to help your local environment — while the fire fed on branches and twigs, it also consumed a garbage bag’s worth of invasive wineberry.
For the Lindheimers, the Edgartown family that hosted the burn, they hope their front yard will become a native plant meadow, an early example of home biochar use on Martha’s Vineyard. Tuesday’s burn was the first at an Island home using biomass from both the hosts’ and neighbors’ yards, and the Lindheimers got out of it a little over 25 cubic feet of biochar — what they hope will help their garden and front yard flourish.
“We moved in a couple years ago, and this was all barren,” Lauren Lindhemer told The Times, pointing out the sandy soil composition of their yard. “And I was very interested in trying to bring a natural landscape back. I didn’t want to plant anything that was invasive, or going to bring the wrong bugs, or butterflies, or any of that stuff.”
Lindheimer was also tired of paying people to take away parts of her trees killed by oak moss, and decided to try biochar after attending some of Craig’s earlier demonstrations.
It also beats ordering a layer of fertile soil from off-Island. “It seemed silly to pay 20, $30,000 to bring in topsoil,” she added.
The fire itself held everyone’s attention on Tuesday, as big fires do, but the real star was the flame cap kiln, a collaboration between Carloni and Craig. Named the Umptopia 3.0, the kiln looks a bit like a dumpster without a roof. Craig and company assembled it on-site from six panels of fire-stained 18-gauge metal, Galvalume, roofing, and barn rail — no brackets necessary.
The kiln is designed for a safe, contained burn, and it allows biomass to be piled intentionally in layers. Medium-sized plant material is placed on the bottom to create a bed of hot coals, and the fire is supposed to burn on the top.
Carloni said that it costs about $2,000 to make the latest Umptopia model, and that he wants to test the kiln thoroughly before bringing it to market. Craig has also set up kilns around the Island for demonstrations.
Their setup is not the only way to get biochar from plant matter, Carloni said, but it is efficient compared to machines used by managers of large, non-residential Island properties such as Philips Preserve in Vineyard Haven. Thirty to 50 percent of the carbon stored in plant matter fed into Umptopia is left behind after burning. “We’re the guerrilla level of biochar making,” Carloni said. “No machines required — very human-powered operation here.”
As the Umptopia or kilns like it could lower the barrier of entry for residents, Craig told The Times that the material has potential for a wide range of eco-friendly uses. Human use of biochar to improve soil dates back thousands of years to indigenous populations, she said, including on-Island, and it has been used in recent years in construction to strengthen concrete.
Craig hasn’t met many Islanders making biochar at home, but she said that Polly Hill Arboretum has made and imported the substance for composting use.
And many gardeners consider compost from Native Earth Teaching Farm to be the best on the Island thanks to biochar, she said, adding that Morning Glory Farm and Slough Farm are also interested in using it for compost.
While replacing fertilizer is a draw for many gardeners, Craig said biochar might also be able to reverse some impacts of past fertilizer use on Island ponds. The nitrogen and phosphorus in fertilizer that help plants grow can leach into nearby waterbodies, and cause algae to grow out of control. This can lead to algae blooms that take up much of a pond’s oxygen, causing unsafe conditions for aquatic animals and other plants.
At Tashmoo Spring Pond, Craig has also just started to work with managers to place a lobster pot with raw biochar underwater next to the nearby pumping station, something Carloni described as a “reverse teabag.” The hope is that this will catch and remove excess nutrients that enter the groundwater from old septic systems and fertilizers.
Mitigating fire risk and helping manage Vineyard forests is another goal key to Craig’s work. As wildfire risk remains a hot topic among emergency planners, Craig hopes to work with Firewise USA, a national program in which town Fire Chiefs assess private homes for fire risk. Burning smaller biomaterial, Craig explained, uses up much of the fuel on the ground that a wildfire would feed on.
If biochar use continues to catch on at farms and homes, it could also go hand-in-hand with other emerging at-home sustainability systems. At last weekend’s Earth Day festival at the M.V. Museum, the Lagoon Pond Association showed off a Urine Diversion toilet, a model that separates urine from human waste. While the toilets are not yet permitted by the state, they’re part of the biochar conversation because the material must be “charged” with nutrient-rich matter before going in the ground. This can be done by adding 10 to 20 percent biochar by volume to your compost, or by adding pasteurized urine.
Back at the Lindheimer’s home on Earth Day, with the fire safely contained throughout the demonstration, the enthusiasm for biochar burns had spread. “I am really looking forward to being able to have a setup like this,” Dawn Greene told The Times. She said that her land, like that of her neighbors the Lindheimers, is difficult to work with. She has experimented with burning plant matter, and plans to only grow native plants. She also harbors a grudge against the invasive autumn olives that grow at her home, and would like to safely set them on fire. “Our soils are really so poor, and there’s really not a lot of diversity, I feel, where we are,” she said.
Craig and Carloni did caution that there is a proper procedure for a biochar burn. Precautions include Carloni’s recommendation to wear non-synthetic materials, just in case an ember lands on you that’s hot enough to burn plastic onto your skin. The Lindheimers also had to obtain a fire permit in Edgartown, something only available to residents in certain months of the year.
But with proper education, there’s hope that biochar could become a movement.
“People are really passionate about it, and interested in it,” Greene said by the fire. “I think it’s really a question of getting the word out, showing people that it’s possible to have events like this.”
This story has been updated to clarify the designer of the kiln and how the kilns have been distributed so far.
