Biochar

Two Simple Ways to Make Biochar

Biochar has been used for centuries to create a stable soil that is full of beneficial microbes and nutrients.
This process is modeled after a 2,000-year-old practice in the Amazonian basin, where indigenous people created areas of rich, fertile soils called terra preta (meaning “dark earth”).

Biochar is kind of like charcoal that’s made by burning organic biomass such as dead wood, brush, and other organic materials. It is black and sooty, highly porous, very lightweight, fine-grained and has a large surface area.
Approximately 70 percent of its composition is carbon. The remaining percentage consists of potassium, calcium, nitrogen, hydrogen, and other elements.
It conditions the soil and creates hiding places for microbes that eventually turn it into rich fertile soil that holds carbon for many, many years.

Just like anything else, the quality of what you put into it will determine the quality that you get out of it. Ideally, clean dead wood with 10 to 20 percent moisture and a high lignin content must be used.
Biochar can retain heavy metals and other chemicals so keep that in mind when choosing your biomass.

There are many different processes for making biochar and I will explain the two simplest ones here.
Firstly is the original method that was used by ancient Amazonians.
Just dig a pit in the ground about 2 or 3 feet deep and as large as you will need for your material. Save the excavated dirt in a pile for later use.
Fill the pit with your biomass and set it a blaze. Let it burn about half way down and until the flame starts to dwindle. All of the material should be well chared but still mostly whole pieces.
Then completely cover the burned material with your pile of soil to smother the flames but allow it to continue to smoke. Leave it to cool until the next day.

Now carefully unearth the burned material and place it in a container.
This will then be crushed and used at a rate of 10% of your soil mix.

The other method that I will explain is the single barrel method.
For this, you will need a metal drum with a removable lid.
Drill 1 inch holes all of the way around the bottom of the side, spaced every few inches.
Prepare clay soil in a ring all the way around the bottom but leave the holes open to breath.

Completely fill the barrel with your biomass and set it a blaze.
Let it burn down until the barrel is about half full and the flame is starting to dwindle. All of the material should be well chared but still mostly whole pieces.
Now push the clay dirt, in your ring, up against the holes in the bottom of the barrel to completely cover them. Then cover the barrel with your lid and place a heavy rock on top. This will now smoke like a mfer. Leave it to cool until the next day.

Now you can remove the burned material and place it in a container. This will then be crushed and used at a rate of 10% of your soil mix.