DIY Biochar in Small Batches

Black Soil Magic is a fabulous and sustainable soil amendment that acts like a sponge to hold nutrients, microbes, and water. BSM reduces leaching and, once made, captures carbon, removing it from the carbon cycle and stopping CO2 release into the atmosphere for years. It is simple to produce from waste products on your plot! Here is a simple, step-by-step guide to making Black Soil Magic (biochar) for free in small batches in the allotment, garden or small-holding, using an open firepit and/or a range of DIY, simple-to-source, inexpensive retorts or kilns.

The scope of this publication covers open pyrolysis of bulk secondary feedstocks with a flame curtain alongside the decomposition of finer primary feedstocks within a Flexi-Tube or small kilns made from baked bean cans shoved together or old paint tins. The colour pictures showing a firepit, feedstock, pyrolysis and crushing of biochar were all taken in Lincolnshire, UK. Secondary feedstocks used to make char included apple wood, briar rose, brambles, sweetcorn plants and fruit bush prunings. Primary feedstocks for decomposition by pyrolysis inside kilns, retorts or Flexi-Tubes included hawthorn wood chips, root grindings, broad bean and runner bean pods, couch grass, horsetail, bindweed, ground elder, dandelion and dock tap roots. How crushed raw char is charged or activated by adding to the compost heap and/or soaking in nutrient weed-liquid ferments is described, along with mix ratios for different circumstances.

Improve your garden soil for hundreds of years to come, while helping reduce climate change and global warming.