I am considering making biochar from my large pile of prunings from our acre in the city. I saw this video on youtube "https://www.youtube.com/watch?v=NrTaISI9fm4" where he makes it outside using a brick chimney kiln. I want to build kiln on a concrete patio we aren't really using.
I want to use the biochar in our garden beds and also fruit tree guilds but our soil is ALKALINE! According to Joe Gardener, "There are good and poor quality biochars available, so purchase with caution. Many biochar products contain ash. The higher the content of ash, the more the biochar material will affect your soil pH. A good quality biochar will keep your soil within the neutral zone, while a biochar high in ash can significantly raise your pH."
How do I determine how much ash will be in my biochar with this method? I want low ash to not raise PH any higher.
I also want to make a bit of biochar in our Quattro wood insert inside during winter using this method "https://www.youtube.com/watch?v=jxBUqk2M3Y8. I bought the hotel pan to put the small pieces of wood in, and the same question applies...is this going to yield a final product with low ash content? Can you tell by looking at it if it is low ash?
Thanks for any help!