Click below to listen to my 2 min. Garden Bite radio show: Biochar
I was just recently on a garden tour of local gardens in my hometown. They were all lovely but there was one in particular that really intrigued as it was not the “usual” garden tour fair. It was strictly about vegetables and this man’s quest for the best.
It’s all in the soil, or will be. He makes his own biochar. What’s that you say? First, I’ll tell you what it’s NOT, it is not ASH.
Basically, it’s organic matter (John uses wood) that is burned slowly, with a restricted flow of oxygen, and then the fire is stopped when the material reaches the charcoal stage. Unlike tiny tidbits of ash, coarse lumps of charcoal are full of crevices and holes, which help them serve as life rafts to soil microorganisms. The carbon compounds in charcoal form loose chemical bonds with soluble plant nutrients so they are not as readily washed away by rain and irrigation. Biochar alone added to poor soil has little benefit to plants, but when used in combination with compost and organic fertilizers, it can dramatically improve plant growth while helping retain nutrients in the soil.
One method of making biochar is to pile up woody debris in a shallow pit in a garden bed; burn the brush until the smoke thins; damp down the fire with a one-inch soil covering; let the brush smolder until it is charred; put the fire out. The leftover charcoal will improve soil by improving nutrient availability and retention. It stays in the soil for millennia and is found all around the world, in particular, the Amazon.
USDA – biochar
Biochar is NOT the “answer” to everything but it has benefits. Here’s another view Earth Island Journal