Biochar Demonstration Beds

The Master Gardener Biochar Demonstration Beds will compare plant growth between raised beds prepared with and without biochar (agricultural charcoal). The project was started in spring, 2015.

Biochar is a fine-grained, carbonized product similar in appearance to common charcoal. It is made by heating a “biomass” such as scrap wood, chips, garden debris, forest slash, etc. to near-combustion using little to no oxygen in a process called “pyrolysis,” or “gasification.”

As a soil amendment, the structure of biochar adds porosity, as well as water and nutrient retention. It also stimulates the activity of agriculturally important microorganisms, increases CEC (cation exchange capacity), and raises soil pH.

Biochar production and use has potential for helping to slow climate change by reducing CO2 and other potent greenhouse gases, and by locking carbon into the soil for many centuries through the process of “sequestration.”

The demonstration beds contain a nearly identical mixture of topsoil, compost, amendments, and plants. Biochar with a known chemical profile was mixed with half the compost and “charged” for several months before being added to one bed; the other half of the compost -- without biochar -- was added to the second bed.

The pH and soil chemistry of both beds are monitored and adjusted as necessary, and plant growth documented.

Biochar Demonstration Project - Project Update