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Biochar By The Jar

Always at this time of year, I am thinking about coal.

I reflect on the proverbial lump of carbonized plant matter that we joke about appearing in our slippers or stockings hung with care. I replay fragmented images of the mythical dirty coal sack stuffed full of squealing naughty children that disappears into the night on Christmas Eve.

As odd as it is that we readily embraced these ideas decades ago, it is not surprising perhaps, for an industrialized society built on coal.

As an adult and urban permaculture designer, I would in fact be happy with a cabonized lump in my Christmas stocking. Not coal, rather a lump of biochar crushed into tiny ice and snow-like flakes and shards.

Biochar provides habitat for microbes, retains water and nutrients, and helps aerate garden soil

Coal was created over the slow and steady passage of millions of years, as dead biomass (plant matter) decayed into peat and was then converted by heat and pressure into combustible rock.

Mining and burning coal en-masse as humans have done since the Industrial Revolution, resulted in what climate scientists report is the single largest anthropogenic (human caused) source of atmospheric CO2 contributing to climate change.

Millions of years old, dead biomass presents as sedimentary coal seams clearly defined in a mine site test cut

According to, an environmental and social justice resource supported by Greenpeace, The Sierra Club, Health and Environment Alliance and other environmental and health organizations, Coal is the single biggest contributor to anthropogenic climate change. The burning of coal is responsible for 46% of carbon dioxide emissions worldwide and accounts for 72% of total  greenhouse gas (GHG) emissions from the electricity sector.

The burning of coal, as in this coal power plant, is responsible for 46% of carbon dioxide emissions worldwide

There is of course no going back to undo damage done, but knowing what we do about carbon and where surplus carbon belongs — underground, not in the atmosphere — can help us sequester carbon in biochar in a way that benefits not only the planet generally, but our food, herb and medicine gardens specifically.

Biochar is a form of charcoal that is made either incidentally or intentionally when biomass is ‘burned’ in a low-oxygen environment. This can happen naturally in a smouldering, earth-covered fire pit, as practiced by pre-Columbian Amazonians across numerous terra preta (black soil) zones, and it can happen through a complex process known as extreme pyrolysis (carbonization).

Burning byproduct or waste biomass in a low oxygen environment produces organic biochar and energy

During my former life as a corporate communicator, I touted mobile and small-scale pyrolysis as a green and productive closed-loop system of biowaste management and energy production for Canadian communities. In hindsight, we were surfing the flat waters of denial a dozen or so years ahead of the IPCC Report-inspired curl.

Permaculturists make biochar in small home-made biochar ovens or in pits. Farm and garden remnants like wood waste, trimmings, husks, leaves, needles, cobs, straw, etc are burned without oxygen, so that the non-carbon cellulose, lignin and fibres gasify, leaving black spun glass-like skeletons of pure and stable carbon.

Examined under an electron microscope, these sponge-like skeletons look like miniature bug hotels. When the biochar is broken down into small pieces and used as a soil amendment, gardens benefit from its water absorbing and retention qualities. Microbes move into the millions and millions of teeny tiny habitats where they can more easily and beneficially work their collaborative magic alongside mycelium and other organic garden partiers.

Pyrolyzed corn cob biochar, a stable and pure form of carbon, before crushing for maximum surface area exposure

The surface of biochar is electrically charged, which attracts beneficial elements that plants need to thrive, preventing nutrients from leaching out of the rhizosphere (root zone) where they would no longer be available to plants.

Biochar in composts keeps odours down, balances moisture, reduces off-gassing, and improves soil biology. Biochar in seed starting mixtures helps retain moisture and prevents nutrient leaching. Adding biochar incrementally to all levels of organic home gardens can, over time, help build healthy, balanced, self-regulating edible ecosystems, and sequester carbon in the soil.

As with all natural systems, the production, management and use of biochar requires thoughtful contemplation about how it exists in equanimity in nature. Only nature knows when to set a forest ecosystem alight to open a canopy, fight disease, eliminate predator insects, balance wildlife populations, or one of countless other prescriptives.

I believe it is wise to defer to nature’s logic in small doses and use pyrolysis as a means of biomass waste management that can also produce so-called clean energy to replace so-called dirty energy.

Peru: conservationist cools biochar to demonstrate alternatives to CO2 emitting slash and burn practices. REUTERS

I do not advocate the production and processing of biomass crops specifically to feed pyrolysis plants, unless of course there is no cleaner energy alternative available locally. Humans already produce more than enough organic biomass to fuel pyrolysis systems — byproducts and so-called waste products from forestry, agriculture, food processing, and urban landscaping — we would be wise I should think, to leave it at that.

Perhaps someday, when public will and environmental legislation reach equanimity, biochar input bins will sit out at our curbs for collection. Until then we do what we can individually and collectively, to sequester carbon.

I have been adding biochar, in small doses to my raised beds and composts, for two years. Homemade — admittedly imperfectly — so there is some quantity of ash that comes along for the ride. Wood ash is not biochar and it is important to recognize the difference.

Viewed under an electronic microscope, my garden variety biochar boasts millions of tiny microbe condos

Wood ash has been used as a natural fertilizer for centuries, and can be a wonderful source of nutrients and trace elements. Wood ash nutrients vary by wood type, and if used directly without pre-composting, can burn plants and adversely alter soil PH. Doing a bit of research and soil PH testing before adding wood ash is advised.

Biochar is an idea whose time has come. We are learning more about biochar in conversations related to the natural wisdom of lightning fires in unmanaged forests, and it relation to controlled burns. We chat about biochar in organic gardening circles, and we see organic farmers and permaculturists incorporate biochar into both small and large scale operations.

Starting early in the new year, I will be incorporating biochar into my seed starting programs — both indoor and outdoor —- adding another layer of natural logic to our urban permaculture gardens. I will add a healthy dose of biochar to spring top-ups in beds and in containers, so that should we be struck again by catastrophic heat waves, our food and medicinal plants should experience less stress.

'Biochar by the jar' headlines a home-grown, home-cured, home-preserved line-up of holiday gifts

For now, back to the kitchen I go to label and assemble gift packs of home-grown, home-cured, and home-preserved garden to table holiday gifts. ‘Biochar by the jar’ in lieu of lumps of coal for both naughty and nice friends who small-scale garden indoors and outdoors, is sure to be a hit.

Happy holidays. Stay safe and warm.

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I just read "The Biochar Solution" and your article in the NS News, and want to try it out in our garden...Where can I buy biochar? Thanks, Alex, 604 998-1045

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