What is Biochar?

The soils of Ancient Amazon “Terra Preta” were poor and acidic and thought to have been improved by the addition of charred organic material by the indigenous people, who farmed the land between 450 BCE and 950 CE. The dark earths soil additive neutralized the acidity in soil, improved water and nutrient retention, while improving drainage and aeration in sandy soils. The improved food yields sustained the population which led to population growth across the Amazon region (RHS.org).

Biochar is an umbrella term for any organic material that has been carbonized under high temperatures (300-1000 degrees C) with very little oxygen. This process of carbonization is called pyrolysis and the end result is a solid residue that is at least 50- 80% elemental carbon (PSU.edu) or biochar. Any material can be pyrolized, and could be a good solution for less desired interruptive plants and trees. 

Biochar is not a fertilizer. Instead, it is a “housing complex for microbes”. Biochar retains much of its capillaries of the original wood or plant material; the remnants of the xylem and phloem vessels. These channels once delivered water and nutrients to the leaves and now provide chambers or rooms that provide shelter for microbes. The microbes hold water, oils, sugars, and proteins and boosts plants ability to take up these nutrients from these reservoirs. 

Jeff Cox, the author of Gardening with Biochar (2019), writes that biochar decreases greenhouse gases. The carbon will stay sequestered in the soil for centuries, reducing the amount and carbon dioxide in the atmosphere, as much as 90%, thus reducing global warming.

Research is ongoing at Penn State University. Here, scientists believe biochar can increase yields by 10% and can be used as remediation agent to capture inorganic and organic contamination in soil or water. Biochar will bind to heavy metals, toxic chemicals, and pesticides. It has been used on abandoned mine sites and roadside runoff. Researchers are exploring how biochar, when added to seed starting mix, can enhance seed germination.  Also, when added to compost heaps biochar can help reduce emissions of methane and nitrous oxide.

One and done. A single application has a life of 1000 years (some studies say 5000 yrs.) Not all biochars are equal. Know what’s in your Biochar. Plant tissue, woody material, and manures are often used, but wood is the preferred medium. Know what your pH level is in your soil, because Biochar could raise that level, but not all biochars are alkaline. Make sure your Biochar is sustainable and certified organic. Biochar becomes more effective when mixed with compost. Mix your biochar with your preferred growing media at a 10% rate and allow a minimum of four weeks before planting, this will allow time for the Biochar to become inoculated and allow time for the beneficial organisms to become established. 

I have used Biochar in my raised beds, containers, and borders. I was curious about biochar after reading that it may be useful in reducing the population of Jumping Worms. While biochar may have a short-term negative effect on the worms, the research does not support biochar as a long-term solution in the control of Jumping Worms. 

For more information:

Organic Mechanics: ORGANIC MECHANICS® Biochar Blend Soil Enhancement (1-0.4-1) - Organic Potting Soil - Organic Mechanics Soil

Available at Natureworks: Learn to Grow and Garden Organically | Natureworks Garden Center