I am often asked what is done with the soot that I remove from the chimney.
Because it is classed as household waste it is often left in the customers rubbish bin. Sometimes people like to use the soot on their allotments or rose bushes. If you want us to leave it for you to do the same then just ask your chimney sweep Alfred Poppins !
The longstanding tradition is to leave the soot to ‘weather’ for about one year. This ensures that polyaromatic hydrocarbons and other substances that could harm plants have time to dissipate.
The UK Biochar Research Centre are doing trials with biochar (horticultural charcoal) and so adjust for the presence of black carbon as soot in order to validate their test results. Soot, once it has weathered, is a fine particle size version of biochar and another way to help build the carbon framework in soil that encourages microbial activity and better soil structure.