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Improvising biochar

 
Rosalind Riley
Posts: 70
Location: Kent, South-east England, UK
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Hi all

I've been looking at biochar as a soil improver - I don't want to make a lot of charcoal myself but I do produce the usual lumps of fragile, fully-charred wood at the bottom of my wood stoves when they go out. So I have had a fitful supply of little lumps of charred stuff over the winter which of course I've just left in to burn when I've next lit the stove.

If I just pick out those charred bits, bash them up and sprinkle them on the veg patch, or dig them in, is that "biochar"? I already spread the stove ashes all over the place (mostly the orchard and on any fruit trees, and of course this includes a proportion of little bits of charcoal) but presumably the ground charcoal should persist in the soil?

Thanks for any advice

Rosalind
 
Todd Parr
Posts: 572
Location: Wisconsin, zone 4
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Technically it isn't biochar until it is inoculated with something "bio", ie soaked in compost tea, etc. That being said, if you just put it in the soil, it will be inoculated anyway at some point, so I would go for it. I've seen people recommend going thru a nearby campground and picking the chunks of charcoal from the firepits. I'm incorporating charcoal and biochar into my gardens this year to see if I can tell the difference.
 
Rosalind Riley
Posts: 70
Location: Kent, South-east England, UK
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Thanks Todd

I can certainly add the bio element - or indeed add the charcoal at the same time as my rather rich and very vibrant home-made compost! Come to think of it I think we have some rather aged nettle gloop as well which could work.

Veg patch here I come!
 
Craig Sams
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Biochar is not called biochar because of adding biological elements. It is called biochar purely to differentiate it from charcoal, i.e it is charcoal for use as a soil improver, not for barbecuing sausages

That doesn't mean it's not a good idea to inoculate biochar with compost tea, mycorrhizae or any other activating material, I'm just being pedantic about the definition. Biochar is just pure charcoal

When we (Carbon Gold) market it here in the UK we blend it with mycorrhizal fungi spores, wormcasts (a rich source of actinomycetes bacteria) and seaweed and we call it GroChar. There are more and more proprietary blends emerging, but biochar is just plain old charcoal that has been made at lowish temperatures and has definitely not been made with old rubber tires, plastic waste or wood that has been treated with preservatives or paint. It has to be clean feedstock.
 
Rosalind Riley
Posts: 70
Location: Kent, South-east England, UK
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Thanks for the clarification Craig!

R
 
Triato Vallejos
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Biochar with ashes will be alcaline, if your soil is acid that is good, if not, measure the char (mix with water and test with paper strips) to make sure biochar will not rise the soil PH to far. Or use les than 5% by volume. Since you already use ashes and see a benefit I think it will be fine.

Crushing to dust is not really necesary in my opinion, just get them to be smaller than the width of a finger.

Consider not only inoculating with microorganisms but with nutrients too (aside from the ash)

Good luck
 
Erich Sysak
Posts: 38
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Rosalind,

Soak it in lactic acid bacteria in a shady place for a few nights and then bury it in the garden. Good stuff. Watch out for the word police.

E
 
ross johnson
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Biochar is similar to charcoal but its different. What it is is carbonized organic matter. If you have a heat source and put something on it in the presence of oxygen then the materiel will catch fire. If you put materiel in a heat source but have it cut off from oxygen, the materiel will smolder and char. Many of the compounds contained in the materiel, will not burn off so the biochar will be a little richer then charcoal.

If that doesnt make sense heres an example-You have a fire outside burning like a normal fie. You fill anything from a dutch oven to a steel drum with organic, cover it so no oxygen can get in and place it in the fire. The heat will tranfer from the fire to the materiel but the materiel will not catch fire because there is not enough oxygen for it to catch fire but the materiel will smolder and turn to char. Carbonized organic matter.

I've got tons of rice and beens that were in a trailor I picked up . Its been sitting in a box outside and is not something I would eat at this point. Carbonizing it would be the most practical use for it.

Once you have biochar or charcoal it is a good idea to soak it in water if not compost tea or something. I soak mine in lactic acid bacteria personally but the point is to moisten it because otherwise it may never really get wet depending on the climate etc. Once it is wet and in the soil, whether its biochar or charcoal it will be colonized by micro-organisms.
 
Kevin Morris
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Hi all,

I'm new to the forum, but have been reading for quite a while researching permaculture. I've been looking into building a small batch biochar retort for my suburban property. I've just read this thread and I wanted to chime in. It is the case that char is left in the ash of incompletely burned wood where, under the ash, it was heated in an oxygen poor environment. This is not the ideal way to produce biochar, but it will work. Break this up and it will benefit your soil (more so when inoculated), the smaller the better, to a point. What you're adding to your is a refuge for microorganisms, so small pieces (small to us) are still large in the micro-world and the smaller you can get it, the more uniformly it can be distributed in the soil.

While the traditional model of charcoal production consists of relatively low temperature heating over a period of several days, research in the US is showing that this is not the ideal way to produce biochar. Ideally biochar is produced in the complete absence of oxygen and at temperatures at or above 450C. This drives off ALL of the volatile compounds and leaves only extremely porous black carbon (the pores store the water, microbes, nutrients, etc...). The more organic compounds left over after pyrolysis, the more likely the char will be to actually repel water. When you crumble it in your hands, the black dust should wash off completely with water alone and should not leave any oily residue. The gasses that come out during pyrolysis should be burned to do some kind of work (heating, cooking, electrical generation, etc...) and not allowed back into the atmosphere. As I said, this is the ideal; I would still put your wood stove char in my garden.

Cheers,

Kevin
 
Jeffrey Hodgins
Posts: 166
Location: Yucatan Puebla Ontario BC
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Studies show that 5% is a good mix for bio-char
 
Fred Winsol
Posts: 155
Location: Sierras
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ross johnson wrote:Biochar is similar to charcoal but its different. What it is is carbonized organic matter. If you have a heat source and put something on it in the presence of oxygen then the materiel will catch fire. If you put materiel in a heat source but have it cut off from oxygen, the materiel will smolder and char. Many of the compounds contained in the materiel, will not burn off so the biochar will be a little richer then charcoal.


Wholeheartedly agree with this. Some people call it 'poor man's biochar': at your next campfire/firepit session, have some dirt ready and cover the white hot coals with around 2 inches of dirt which is in effect cutting off the oxygen quickly - the methane (producer gas) gets sequestered into the coals and you have RICH biochar. You'll have to wait a couple days for it to cool down and then I usually bury the chunks between 6-12" into the vegie areas.

Last year I attended the International BioChar conference and was amazed to see many attendees from the Midwest USA, Asia + S.America: turns out it is big business this biochar and results in 'carbon credits' BioChar will have a very important role in restoring our depleted soils - like the Mayans did.
 
Rosalind Riley
Posts: 70
Location: Kent, South-east England, UK
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Hi all

I realise there have been several replies on this post which I haven't seen - for some reason I haven't been notified so have only just read them. Just wanted to say thanks.

Rosalind
 
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