See what we’re doing in my latest video, then read on for a transcript and further notes:
Welcome back. If you’ve watched my channel for any period of time, you know that I have terrible soil. I also have two smart friends named Steve – Steve Solomon and Steven Edholm, the former being the author of many gardening books and the latter being the creator of the Skillcult blog and YouTube channel. Both Steves recommended I add biochar to my garden in order to improve it over time and to increase the exchange capacity of my sand.
This is all well and good, but in order to get biochar, we have to make it. And because we’re cheap, we want to make it for free!
Over the years I have have seen many biochar-making systems ranging from cones to kilns to burning wood in a smothered trench. Though I am no expert on the intricacies of biochar, it’s really just charcoal with a fancy name, and there are many traditional charcoal making systems which are usually labor-intensive.
I don’t have time for all that. I need a lot of biochar for my garden and I need it for spring.
Having seen the “Kon-Tiki” biochar cone method developed by Dr Paul Taylor and Hans-Peter Schmidt, and Steven Edholm’s trenching method, I decided to dig a small conical pit in a sandy area out back and burn biochar in it. We don’t have the resources to go making a big metal cone right now and for the scale we need, it’s probably unnecessary, though I would love to have one. So we’re going the free route and digging pits to burn in. After doing so and creating multiple batches in a short time, I turned the process over to my children to do and now I hire them to make biochar for our gardens.
It’s really quite simple to make biochar this way.
First, dig a nice little pit with sloping sides within reach of a water supply. Our pits are a couple feet deep. Then gather your fuel and cut it into short lengths that will fit nicely in the pit. Branches around an inch to an inch and a half in diameter seem to work best. You’re going to need a good pile of these. Gather some small sticks as well for the first stage of the fire.
Now get some paper or pine needles or leaves or itty bitty sticks or whatever you have and put it in the bottom of your burn pit and light it. As it fires up, feed it small sticks. Once these are flaming, start to add larger ones.
It makes sense to progress in layers. What you want is to get one layer burning well and turning black before adding the next layer on top. Keep the layers flat on top of each other, encouraging the fire to burn to the edges of the pit. Each successive layer chokes off some of the air from the one beneath, keeping it from melting away into white ash. Add layer after layer until you reach the top of the pit, then give that last layer time to burn until the sticks are glowing red and starting to turn to ash around the edges.
When you hit that stage, soak the fire with water, extinguishing it completely. Don’t quit wetting it until you are really and truly sure the fire is out. If it stays lit beneath, you may have the whole thing re-ignite and burn away into ashes while you’re not paying attention.
One the coals are cool, get rid of any un-burned chunks of wood you see. There are usually a few sticks that didn’t burn all the way down into charcoal.
If you like, you can start crushing the char. I don’t bother because it’s too much work, though I plan to experiment with some crushing systems in the future.
Now that you have your biochar, it’s time to charge it by letting your biochar soak up minerals and/or biological life so it doesn’t eat up the nutrients in your soil. If you plow biochar right into a garden bed, it will soak up lots of fertility and render your vegetables very unhappy for a year or more.
I had very good success soaking my biochar in Dyna-Gro, which is a balanced liquid fertilizer used in hydroponic growing. It has 16 elements in it which provide all that a plant needs to grow.
I’m also adding Neptune’s Harvest Fish and Seaweed fertilizer to get extra trace elements and some biological activity, along with a quart of kelp meal as well as a cup or so of pink Himalayan salt. All the minerals of the ocean right here.
You can charge your char with a variety of things, including soaking it in manure tea or urine. You can also take the long approach and add char to your compost pile, letting it absorb lots of nutrition while also being colonized by bacteria and fungi. With my last batch of biochar I dumped the charcoal into a drum of Dave’s Fetid Swamp Water, which is an anaerobic compost tea I make regularly. It’s free, and you can learn how to make it in my book Compost Everything or in some of the other videos on this channel.
Make sure you soak your biochar for a couple of weeks at least, then you can spread it on your garden beds and fork or till it in.
Congratulations – you’ve now improved your soil for a long, long time!
Biochar Resources Mentioned in the Video:
Neptune’s Harvest Fish and Seaweed Emulsion: https://www.7springsfarm.com/neptunes-harvest-liquid-fish-seaweed-fertilizer-2-3-1-1-gallon/
Steve Solomon: https://soilandhealth.org/
Steve’s Books on Amazon: https://amzn.to/3roPxiU
Steven Edholm’s Simple Biochar Trench Method:
Biochar Revolution Kon-Tiki Biochar Kiln video:
Notes from Steve Solomon on Charging
On my video, Steve comments:
“I wish you’d stated the concentration of your soak. I like to soak fresh char in something like DynaGro diluted to 3x to 4x more potent than the recommended dilution on the label, and let it soak for as long as the char is swelling up. I’ve seen that happen for up to six weeks. that way not only are all the exchange points on the char holding plant nutrients, but the solution has also entered into the pore structure. Then the bits of char act like storage batteries slowly releasing plant nutrients for months.”
To which I replied:
“That is about what I did – 3-4x concentration. There’s always something I miss. But hey, I have smart friends. Also, my yield on a little pit burn is about ten gallons of finished char, which is then thrown into the barrel to soak. I use the pond water since it has more life in it and does not have fluoride and chlorine.”
There’s no excuse not to make some biochar and do your own experimentation. After seeing how charged char grew vegetables in my fall garden – and how good they tasted – I am sold.