Re: Minimal prep of biochar for gardens #garden

Tomaso Bertoli - CISV

by now it should be common knowledge that it takes time for biochar in the soil to age and develop bacteria and fungi that help plants grow


I believe it would be so much better to follow the “mineral fertilizer” slow release strategy and \ or the “biological activation” strategy


Nevertheless, Kevin, (not a rhetorical question) what is the purpose of testing “raw” “bone dry” “off the stove” biochar ?


Paul, if I were you


I would find more interesting testing soaking different ration of the same “mineral fertilizer” say 25% or 50% of the suggested rate and compare with the fertilizer alone


I would find more interesting screening the biochar in half and using the finer half in one plot and coarser half in a second plot with the same rate of “fertilizer”


I would find more interesting testing \ experimenting soaking the biochar with compost tea or other “biological active mixes” rather than using a “mineral” fertilizer  


All the best




Da: <> Per conto di Kevin Chisholm
Inviato: martedì 21 aprile 2020 05:41
Oggetto: Re: [Biochar] Minimal prep of biochar for gardens


Hi Paul


I understand that you (or your Wife) had a garden last year. If so, I would suggest the following:


1: Seize an area of the garden, say 3’x12’, for your own growing trials.


2: Divide it into 4 plots, each 3’x3’. Label plots 1,2,3and 4


3: Configure an experiment of some sort. (For example:

  • Plot 1 = “Control Plot”
  • Plot 2 = Plot with “X” grams of “as-is biochar”
  • Plot 3 = Plot with “X” grams of “As-is Biochar” soaked in “Y” grams of Miraclegrow
  • Plot 4 = Plot with “X” grams of biochar crushed to 100% smaller than screen door screen, to which was added “Y” grams of Miraclegrow.


4: Plant any one kind of vegetable in it… tomatoes, beans, carrots, turnips… and see which plot gives the best weight of yield.


Are there any obstacles that would prevent you from running such a test? If the results of such a test set are not of importance to you, simply structure another test program.


Be well, and stay well!




From: [] On Behalf Of Paul S Anderson
Sent: April 20, 2020 11:33 PM
Cc: Anderson, Paul <psanders@...>
Subject: Re: [Biochar] Minimal prep of biochar for gardens




Your message has saved me from a home-made “mess.”  


The coffee-liquid coating is a nice touch, but it is a step I was hoping not to make. 


So far, char into compost and let it sit for at least months seems to be the “best” method.   Not what I was wanting to hear.  


Nobody is saying:     Put fertilizer (inorganic or manure) onto  the soil when you put in some biochar to counter-act the loss of nutrients from the soil into the char in that first year.


Not sure what I will do.




Doc / Dr TLUD / Paul S. Anderson, PhD --- Website:

         Email:  psanders@...       Skype:   paultlud

         Phone:  Office: 309-452-7072    Mobile & WhatsApp: 309-531-4434

Exec. Dir. of Juntos Energy Solutions NFP    Go to: 

Inventor of RoCC kilns for biochar and energy:  See

Author of “A Capitalist Carol” (free digital copies at

         with pages 88 – 94 about solving the world crisis for clean cookstoves.


From: <> On Behalf Of Caludia Kammann via
Sent: Monday, April 20, 2020 5:29 PM
Subject: Re: [Biochar] Minimal prep of biochar for gardens


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Nando, Paul et al.,


Not advisable to let it sit too long -  biochar is alkaline, and mostly the mineral fertilizer mix with biochar starts to reek of NH3 (NH4+ shift to NH3 due to high pH). It’s different with organic nutrients, i.e. compost.


If you want to use mineral nutrients, I advise to cook a solution of organics such as tea leaves (spent or otherwise), coffee leftover or something alike, soak the biochar in the solution and let it dry up. Then mix with your fertilizer in such a way that most of the liquid is soaked up and apply it to soils quickly (in one day). Check the pH – too alkaline, put into alkaline soil, is not good, you lose the N.


We had a nice  nitrate retention against leaching when the biochar was coffee-liquid coated before it was put into the soil.


best, Claudia


Von: <> Im Auftrag von Paul S Anderson
Gesendet: Dienstag, 21. April 2020 00:04
Cc: Anderson, Paul <psanders@...>
Betreff: [EXTERN] Re: [Biochar] Minimal prep of biochar for gardens


Nando (and to the others who have replied),


Nothing special in my vegetable/ flower garden efforts.   Minimal effort.  What should be done (thinning and plucking lower sucker leaves) generally does not get done.   And not organic.


What about putting the biochar into a container and mixing in store-bought fertilizer.   With some water.   Let it sit for a week.   Then spread the biochar.    Any pros or cons to that?




Doc / Dr TLUD / Paul S. Anderson, PhD --- Website:

         Email:  psanders@...       Skype:   paultlud

         Phone:  Office: 309-452-7072    Mobile & WhatsApp: 309-531-4434

Exec. Dir. of Juntos Energy Solutions NFP    Go to: 

Inventor of RoCC kilns for biochar and energy:  See

Author of “A Capitalist Carol” (free digital copies at

         with pages 88 – 94 about solving the world crisis for clean cookstoves.


From: <> On Behalf Of Nando Breiter via
Sent: Monday, April 20, 2020 10:57 AM
Subject: Re: [Biochar] Minimal prep of biochar for gardens


[This message came from an external source. If suspicious, report to abuse@...]



I'm curious. What do you normally do when preparing a garden bed? Are you following a more conventional path in terms of fertilization or using permaculture techniques?


I assume your char is produced at a higher rather than lower temperature range, correct? If so, it may have a tendency to adsorb and retain nutrients from the soil solution in a way that will not be plant available, deep in the pores, particularly if the particle size is not reduced to a rather fine powder, as the internal pore structure will be more developed in a higher temperature char. I suspect that once a mineral is trapped "deep" in a pore, deeper than say 50 microns or so (the depth to which the soil solution seems to circulate more freely as evidenced by the depth to which microbes survive in pores) it is much more likely to remain unavailable to plants, particularly as these pores become clogged over time.


If you are curious if this may be the case, you could set up a small trial with tomatoes for instance in pots, perhaps 4 with your char and 4 without. Don't fertilize them. If the growth and productivity of the tomatoes with char is reduced, then you might assume the char is adsorbing scarce nutrients from the soil solution in a way that the tomato plant cannot manage to access again. 


If you grow tomatoes, you could try this. Plant the tomatoes, spread the char on top of the soil and work it into the surface of the soil. Head off to a nearby stand of trees and collect some leaves, and use that as a thick mulch over your tomato bed, building up as the plants grow to a good six inches or more. Hopefully the leaves will inoculate the char and the soil with mycorrhizae.


Next year, repeat the same procedure in the same bed with the same crop. No need to dig the soil, just work the biochar into the top few inches so it is in contact with the soil, and layer leaves on top as a mulch. As you trim the suckers and bottom leaves of the tomato plant, add more leaves so you get a nice thick layer, like you might find in the forest. 


You could of course use the same technique with other vegetables, as appropriate, if you have enough char and leaves, broccoli, kale, zucchini. 

You could also sow a winter rye cover crop, as shown below in my beds. This will keep the biological soil life alive and productive through the winter months, mining soil minerals and making them available to the soil solution, so at planting time in the spring, your soil is minerally and biologically ready for your productive crop. Just before planting, cut the rye at the base, lay it flat as a mulch, add your layer of char on top, work it in a bit, and then plant directly into the bed, and add a leaf mulch when the plants are mature enough if appropriate. I don't add leaf mulch, for instance, for onions or lettuce or beets, but rather a layer of compost (from horse manure).



What I'm doing here is gradually building up the soil health. I'm not aiming to use the biochar itself as a magic solution for a single crop, but as a part of a strategy to produce a terra preta like result without excessive effort. I've noticed that the surfaces of the larger char oxidizing in my topsoil have become more powdery. I suspect as the years go by, that very fine powder, perhaps in the 10-20 micron range found in terra preta soils, washes down into the soil and immediately binds with other soil particles into aggregates. If I can encourage a mycorrizial network to form with fungal nutrients like leaves, this may help to mine and transport minerals from the large char particles. Incorporating these fresh particles near the surface, rather than clustering them close to the roots, would prevent the char from adsorbing nutrients from the root zone. 


Going forward, I will crush my char into as fine a particle size as I can manage. I don't see the particles breaking down substantially over the years, but only becoming a bit more powdery on the surface as I've described. It has the texture of a soft chalk after 4 or 5 years. This will distribute the char much more widely in the soil, signficantly increase the exposed surface area, potentially by several orders of magnitude, make any adsorbed minerals much more easily available to the soil solution, and promote soil aggregation, the char becoming deeply integrated into the soil matrix rather than sitting in the soil separately, like a small pebble. 


On Mon, Apr 20, 2020 at 2:45 AM Daniel Pidgeon <daniel.pidgeon@...> wrote:

Hi Paul,


I echo Robert, as also being an untested amateur.


Even though not interested in compost (because of the bulk and turning required?), maybe one of those black plastic, stackable tray worm farms might offer a better solution for disposing of regular kitchen scraps and charging biochar at the same time? Small enough particles go through the  worms gut, too large pieces simply soak in and adsorb up the resulting goodness. No turning required, just add scraps and some dry carbon material bit by bit, and unload when done. I know those bins might not be what a proper worm farmer like Mike might recommend, but it is convenient. I have mine in the corner of the garage so as to not fry them in the Australian summer, and though I don't get/have much char, it all goes through one or another of the compost systems. Just yesterday I lit the fire pit, did some marshmallows and hot dogs with the kids, then made sure to keep a flame cap going for a bit to build up the char. Quenched, buried and soaked it in fresh grass clippings, and now it's in one of the compost bins.


Or, in connection with another thread going on at the moment, you could simply pop one of those char buckets down behind the shed, make sure to rehydrate plentifully when gardening, and when nature calls... If Mrs Anderson has a problem with you doing this, maybe mumble something about "prostate" and "70 something years"...


But in all seriousness, a biochar use "fact sheet" would be amazing. When I started to learn of biochar a couple of years a go, it would have been a boon to read the filtered down expertise and experience of many decades collectively in this field, rather than stumble blindly through tens of hours of internet searches and Youtube videos, and try to discern who may or may not have known their stuff.


Kind regards,

Daniel Pidgeon

From: <> on behalf of Gordon West <gordon.west@...>
Sent: Monday, 20 April 2020 9:59 AM
To: <>
Subject: Re: [Biochar] Minimal prep of biochar for gardens


Hi Paul,


Thanks for presenting a scenario that is probably far more representative of a more common potential char user that all of us Charista geeks.


One suggestion would be to talk to folks who do compost and offer to give them biochar to put in their compost in exchange for some of the finished product.


Gordon West

The Trollworks

503 N. “E” Street

Silver City, NM 88061



“You never change things by fighting the existing reality. 
To change something, build a new model that makes the old model obsolete.”  
– R. Buckminster Fuller







On Apr 19, 2020, at 12:15 PM, Paul S Anderson <psanders@...> wrote:


Dear Biochar experts on preparation of biochar,


I seek a minimalist approach to preparation of biochar for gardens.  Please teach me.   Shame me (gently) if necessary.   I expose my ignorance and ask for help.


NOTE:  If this is not an appropriate topic for the Biochar Discussion Group, please say so to the group or to me directly and then we can take discussions off-list.   But I think that messages from a few of you could be of interest to many (or be combined into some “fact sheet” that could be circulated with information about how to produce raw biochar).


1.  I have char.   I make char.   I can help others make char with TLUD or RoCC kilns.   But that is about as far as I go.  

2.  RAW biochar onto soils is known to not be good.   So, I want to “charge” the biochar or improve it with the easiest and least expensive ways.

3.  I do NOT have a compost pile, and not likely to have one.   I do bury some  kitchen waste (not from meat), but that is a small effort.

4.  My wife and I will not be collecting urine.

5.  The char is chunky (average half-inch dimensions).   Driving over it with my car in my driveway is not on my to-do list.

       Above is the starting point, and I suspect that there could be many folks like me (except maybe not yet making char.)


Options for improving the char before putting it into the garden beds;

A.   I can purchase in  bags the typical garden supplies.   

                Manure, NPK fertilizers, peat (rather not use peat), Miracle Grow, other artificial or organic plant food, or you can say what to get. 

B.  Can I just put it (which ones and in what amounts?) in a container with the biochar (plus some water)?   Just mix it in?   Let it sit for how long?

C.  Please do not send instructions to purchase commercial products with biochar in them.


I am not planning on having serious control plots and experimental plots for quantitative measurements, but I might have a couple  of “patches” with different applications and then hope for visual differences or notable production differences.   All of my garden plots have had vegetables or flowers for numerous years.


I live in central Illinois and my soils here are considered to be very good, but a bit “heavy” and clumpy when tilled with a garden fork or shovel.   So in  part I want the char to help loosen the soil.


Spring is sort of here.   Will want to plant soon.   I have maybe 25 gallons (5 of 5-gallon buckets, or about 100 liters) of biochar from wood.


Thanks in advance for any thoughts about this.   










Doc / Dr TLUD / Paul S. Anderson, PhD --- Website:

         Email:  psanders@...       Skype:   paultlud

         Phone:  Office: 309-452-7072    Mobile & WhatsApp: 309-531-4434

Exec. Dir. of Juntos Energy Solutions NFP    Go to:  

Inventor of RoCC kilns for biochar and energy:  See

Author of “A Capitalist Carol” (free digital copies at

         with pages 88 – 94 about solving the world crisis for clean cookstoves.



Image removed by sender.

Nando Breiter
CarbonZero Sagl
Astano, Switzerland

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