We are not allowed to make open fires here at all or you'll get a visit of the rural fire service. So in order to make biochar I need some sort of a kiln. I would use the smaller prunings which are not
suitable for heating the house only, nothing over 3 cm would go into the kiln. It should not smoke (we have a bad neighbour around here) and it should be easy to build.
I can get these normal drums for $3each.
I think I can get every amount of trimmings simply asking gardeners around here, but I do not want to cut them endless with the secateurs.