As the owner of a bush block, I do a lot of burning off. When summer comes, bushfire is an ever-present worry, so keeping the bush free of fire fuel is a priority. A lot of pruning and raking of litter gets done on a regular basis throughout the year. I’ve always felt guilty about all that CO2 going back into the atmosphere when it should be sequestered in the soil and stored there.
Enter biochar. Some of you might have read about its value as a soil amendment and a means of keeping carbon in the soil. Here’s the Wikipedia entry on it. Making my own seemed like it wasn’t going to be easy, because of the need to burn material without oxygen to produce pure carbon and not CO2. So I gave the idea a miss.
Then I discovered you can actually buy a kiln in which to burn the material.
https://www.longleyorganicfarm.com.au/biochar-cone-kilns
I checked out the video at the site. It looked easy, so I took the plunge and ordered one. (Note: I wrote this draft a couple of weeks ago and couldn’t do any burning off to try the kiln, because it wouldn’t stop raining! When the weather finally dried up, I went back to the site to check out the video again and got a message saying it was unavailable. I’ve emailed the company to ask why, but if you can’t see it, there are plenty of still photos)
It came in a flat(ish) pack of four bent sections of heavy steel with a bag of nuts and bolts. It weighed a ton! I couldn’t lift the package! But all was OK; I opened it and put the panels one at a time into the wheelbarrow. It was obvious it was going to have to be put together at the final burning-off site.
I managed to do it without having to ask a neighbour for help (it’s awkward to deal with because it’s a cone, but I propped it against a tree).
Finally, I got to try it out.
Here’s the fire just about died down. I only managed to half fill it :
I added the water. A lot of steam….. :
…..and kept adding till the steam and the sizzling noise stopped :
It really is charcoal! It crumbles :
I’ll be using this as a soil additive in all the wicking boxes and tubs and the raised beds I’ve bought for more veggies.
Quite happy with my new toy!
Foodnstuff 