Mineralizing your biochar

In Albert Bates' new book, Burn, he talks about mineralizing as a step in making biochar:

Activating the Biochar
An important point not to be overlooked is that when you're using biochar for agricultural purposes, you first need to charge or activate it before you put it into the soil. (It does not need to be activated when used in building materials.) As explained by Bates, the "Four M's" to remember are:1
1. Moisten — Moisture must be added to the biochar. Fresh from the kiln, biochar is bone dry and hydrophobic (water-repelling). To make it retain water and support microbes, it needs to be made hydrophilic (water-absorbing) again, and this is done by adding sufficient amounts of water, without making it waterlogged. Typically, water is added to the kiln to cool it and stop the fire.
2. Micronize — Next, the biochar must be broken down into a smaller size through crushing, grinding and screening. Smaller particle sizes increase the surface area and allows the biochar to retain more water and allows for greater ion penetration.
3. Mineralize — Lastly, you need to mineralize it, meaning you need to add to it the minerals your garden needs, such as rock powder or sea minerals. That will provide the microbes' the nourishment they need to thrive. It will also add to the plant stores in your garden, allowing your plants to thrive.
4. Microbial inoculation — Next, you want to add microbes, fungi, bacteria and nonparasitic nematodes. These are aerobic bacteria that can be added through a compost tea. Alternatively, you can add the biochar to your compost pile.

I haven't been doing this.  TOday, I think I might add some ag lime or crushed oyster shells to my biochar to see if it might help.

Is anyone else doing this?

Thanks,
John S
PDX OR

Somebody told me about adding glacial rock dust and azomite.  Also with adding biochar you add less fertilizer, because it's not as much needed.

I have been adding the ag lime, not only to the biochar as I am preparing it, but also to the biochar I have added this year.  I can still see the outline of it around the tree dripline.  I have been adding it just before rain so it doesn't blow away. It works pretty well here that way in the Pacific North wet.  Glacial rock dust may be next.

John S
PDX OR

John Suavecito wrote:In Albert Bates' new book, Burn, he talks about mineralizing as a step in making biochar:
2. Micronize — Next, the biochar must be broken down into a smaller size through crushing, grinding and screening. Smaller particle sizes increase the surface area and allows the biochar to retain more water and allows for greater ion penetration.
PDX OR

What is the most efficient way to achieve this? Smashing it with a hammer, or is there a more mechanical or automatized way?

indeed you do have to activate with minerals and microbiome organisms, how you do it can be simple or you can do it in steps as you laid out John.

I have an old water trough that holds about 100 gal. of water that I use for charging fresh made char but I do a one step inoculation of my char.
I fill the trough about half way with char then dump in two coal scoops of finished compost then I add water to cover the char and compost.
That will sit for up to two weeks then I suction off the liquid and use it on garden beds, the char is mixed with compost and spread where I want it.
I like your plan, adding minerals is never a bad thing as long as you know the starting point.

Note: most microbiologist consider additions of minerals mostly unnecessary because of the mineral content of soils is considered by them to be already present but unavailable without the microbiome.
My personal take on this is that you will not find a complete mineral base (complete meaning 97 minerals, soils tend to only have 74) on dry land (not ocean floor), so I think we need to make sure our soil has all minerals available to the microbes.
Most here know that I use Sea-90 for mineral additions since it has the 97 minerals I want available to my plants.

Redhawk

Lukas Rohrbach-Check out the thread "Advice on crushing biochar" and some of the other threads.
John S
PDX OR

John Suavecito wrote:Lukas Rohrbach-Check out the thread "Advice on crushing biochar" and some of the other threads.
John S
PDX OR

You can find that thread here!

I'm still quite new to biochar and have only made a few batches; mostly from leftover charcoal from my little campfire pit I use when I'm working outside when it's cold.
Generally I mix some urine with rabbit manure or compost in a 5 gallon bucket and scoop the coal into the bucket (either hot or cold coal) until it's no longer "soupy", and stir to mix well and break up the larger chunks. Then I leave overnight & by morning I find almost all of the liquid has been absorbed into the coal.
After that I just scoop it out of the bucket and put on the soil surface (under mulch), or dig it in the first few inches of soil.

Does this work for inoculating/mineralizing the coal to make it actual biochar? The finished product size usually ranges from small chunks (like pebbles) to a porridge-like substance at the bottom of the bucket.

I do make the biochar a little more carefully to make sure that I get a higher percentage of crystallized biochar with the volatile oils and wood gone.  That leads to more surface area, and therefore, more "hotels" for microbes.  

I think you are using good stuff to inoculate it with.  I have had that experience, Kc, where the inoculants are all soaked up right away.  That makes me think that I should inoculate it a bit more.  So I usually keep it inoculating for a month or so.  I keep the "inouculant soup" in a ceramic bucket and douse my biochar every few days with it, then pour off the excess.  That way, it retains the aerobic nature that Elaine Ingham says leads to oxygenated microbes that favor crops and food for humans.  After about a month, I dig it into a circle dripline around the trees.  I will start to dig it into my vegetable raised beds, probably next year, once I have finished with digging it into my alkaline/neutral preferring fruit trees.  

John S
PDX OR

Thank you, John, for sharing your process. Next time, I'll follow your example and extend the time of the inoculation while keeping it aerobic to favor the development of an oxygenated microbial system.

A couple of other finer points that Albert Bates went through after listening to the entire broadcast again. Partly it's because with biochar and active microbiology, the minerals you add to the soil don't get washed away as rapidly as they normally would in an average soil.   The reason for the mineralizing is because your biochar in the soil keeps them like a "bank" of nutrients to be stored until later.  Due to how well it enables mycelium to spread,  the bank of minerals will stay there to be used by the mycelium whenever the exudates from the plants encourage the microbiology to seek out that mineral.  

He also emphasized making sure that the inoculation was aerobic, to make sure that the microbes contained are in line with those that promote human health.

John S
PDX OR

What I am realizing in my attempts to document and measure the results of these amendments is that it is much easier to add the minerals in the slurry before you add it to the soil.  I have been trying to add some afterwards and you can't even find where the dripline circle of biochar was. On some of these, I added the biochar more than one year ago.  I have often added wood chips on the surface, so it's hard to see.  The nice thing is that if you all try this after us, you can learn from our mistakes.  On the next batches, I will be adding amendments during the inoculation, not after it is put into the ground.
John S
PDX OR

I am experimenting with making  small scale Biochar in a Dutch oven in our woodstove and combining it with the peppered ash of Convolvulus (bindweed) also peppered the same way in the dutch oven in the woodstove. The Convolvulus has spread rampantly thru mulch in the orchards so I hope to both activate the microbes and stunt the spread with this combo.

Anything extra or invasive is a great thing to make into biochar.  It will still provide "housing for microbes" and it isn't taking down or removing anything productive in the ground.
John S
PDX OR

I’ve never been convinced by the claims that biochar must be finely ground to increase surface area. The whole point of making it is that the char has an inherently high internal surface area, due to the naturally porous nature of properly made char.

Grinding it may make it easier to handle and apply evenly, but I wouldn’t expect a substantial difference in available surface area.

You don't have to make biochar the best way for it to do any good.  Don't let perfect be the enemy of good. It will work better, just like things cook faster if you cut them into smaller pieces.  Potato slices cook faster than a whole potato.  It's not required though.
John S
PDX OR

Michael, the surface area of any bulk solid material increases as the particle size decreases. Crushing biochar does not change its internal structure, but it does maximise the external surface:volume ratio of the grains, and this is a good thing because it means more entryways into the recesses where our tiny friends take up residence. This doesn't mean it all has to be ground into powder. I use a 4mm screen and what falls through it ranges all the way down to dusty fines (except it's nearly always damp so it's more of a slurry). Bigger chunks might get rolled again, but once they're down to pea size that's good enough for me and I like these for potting mixes anyway.

i have to agree with John, I doubt that the originators of terrapreta worried about adding minerals to the char resulting from burning their trash dump. As with any part of soil building, plant growing, animal raising, etc. one can loose focus by worrying about every possible detail. My own ancestors knew to provide their plants with the food needed to thrive.

I've heard  that autumn leaves are a good source of minerals for soils.
They make a great  compost anyway, and are easy to get a hold of around here.
I have added clay soil to my compost in the past and I have read that clay pot shards are a part of what goes into the terra preta middens.
It occurs to me to wonder about the pore structure of low fired earthen ware.
I believe fired clay balls are used in soil-less growing due to their porosity.
Grog made from low fired earthen ware might be a good soil amendment.
I don't know if any mineral content would be available.