Well as Biochar is still not what I would class as a main steam product, finding it down at your local farm produce or gardening store is going to be a little hard, Some charcoal products can be found but care has to be taken as some of these products contain chemical’s which help in the starting of BBQ’s etc.. I’m yet to see Biochar stocked anywhere, but companies like BlackEarth Products now sell Biochar online and via some retail stores in Australia. If you know of any safe cleanly produced product’s please feel free to let me know.
That leave’s two other options that I could suggest, First is to make it yourself which I will cover a little later, the other is to raid old burn off’s
Raiding old burn off’s, these sites can be often found on small lot acreages, farms both big and small and anywhere with a large amount of mature trees, Yes I know… burning biomass is a no no, but for what ever reason people see old dead trees and biomass as something to get rid of, something to burn, while I will often raid neighbours burn piles for garden edging and feature logs in my food forest, some of these piles are 5m high and I just run out of time and energy trying to move large dead tree’s by hand.
What I do instead is check what is being added to these piles making sure it’s all clean timber, removing old farm posts, CCA treated timber or plastic rubbish. Most of my neighbours are pretty happy for me to turn up with my ute and remove the large pile of ash and wood char left after a fire. While this is not strictly Biochar the structure of the wood char seems to fit the structural profile of Biochar, plus the ash is quite alkaline which is great for my acid soils once added and mixed into compost.
Try contacting your local bush fire fighting crew, our local crews often get paid to watch over these burn off’s, a friendly phone call and offer of a case of Beer will lead to some great sources, water added to the pile before it all turns to ash could turn into an easy 1 or 2m3 of wood char and ash. Once again please check the pile as some of those old farm posts or power poles had some really nasty chemical used on them and that’s the last thing you would want to add into your organic food growing soil.
If you are certified organic this method might go outside of your certifier’s rules so I would suggest making it yourself if your certifier allows Biochar.
Making Biochar yourself.
The two key words I would read up on would be either Gasification and Pyrolysis, these two method’s are the most common basis for the production of Biochar and a Gasifier wood stove might be a good start in producing small amounts of Biochar for your composts.
Here is a 44 gallon drum retort design which burns the wood gas creating a clean-ish outcome. If your handy with a grinder and welder you might be able to make one of the many charcoal makers that can be found on Google. The main rule with the production of Biochar is to flare the woodgas so you create a much cleaner burn releasing fewer chemical’s into the atmosphere.
Care has to be taken when producing Biochar, as these system’s get really hot as I have found out the hard way, they also produce wood gas which is a highly flammable gas, I have seen a 1m high flame flare out the top of my system during development, second’s before one flare my good friend Anthony had his head over the system wondering why it was smoking. Experience and a loss of my eye brows saved Anthony from losing his.
My Biochar making system is a fully working prototype, we are at stage one of three. Stage one was to develop a robust low tech system which produced quality Biochar cleanly. Stage two is under way with major parts arriving with in the next week (hopefully) This stage is designed to upscale and refine prototype one, plus allow development and engineering of biomass and Biochar handling. Stage three (which seems so far off) will be to design a user friendly product for the mass market, at this stage a 100 litre batch system is the aim keeping within the bounds of a 44 gallon drum without the need for gas or power, I’m hoping for a low production cost too, just a few hundred dollars.