How to Slow Burn Plants to Make Charcoal

Dig a fire pit at least 6 inches deep, 3 feet wide and 5 feet long with a shovel. It needs to be large enough to hold all of your organic material. Keep the dirt you removed from the pit nearby. Line the pit with large rocks and fill it with your smallest, most flammable organic material.

Light the small organic material on fire with matches or a lighter. Add larger pieces of your organic material a little at a time once it is burning steadily. Allow each addition of material to catch fire before adding more. Continue until all of your material is burning in the pit.

Allow the fire to burn for about 10 minutes or long enough for embers to form at the bottom. Shovel about 1/2 inch of dirt over the fire, carefully, to dampen its flames. Watch the fire closely while it smolders for one to two hours, or until all of your organic material has charred.

Shovel the remaining dirt over the fire, covering all exposed material and embers. Allow the fire to burn out over the course of 10 hours. Check on the fire at least twice per hour to ensure no embers have become exposed. The retained heat continues to burn the material, finishing your biochar.

Remove the dirt shoveled over the biochar when the area is completely cooled. Shovel the biochar out of the pit and into a container for storage until you are ready to use it.