It somewhat depends on which charcoal you use, for example those brickettes used to grill should not be put not your soil while real wood charcoal could be. However a professor of soil science I correspond with who teaches at the University of Illinois and one in Ireland have both stated recently that the idea of adding charcoal is vastly overrated and based on flawed research. Many Ag Schools are having problems replicating this research that showed improved growth.

Then again many ag schools have trouble replicating the success that organic and holistic farmers have, too.

Wow! I have read every topic posted on this site and truly thought that inteligent discussions took place here. This is to bad. First, charcoal can easily be made at home from virtually ALL organic matter, therefore, you do not have to buy it. Second, I spent some time this morning with a farmer who has about a 10 acre field in which the 'dirt' is as black as night. He says this: 1 the farm has been in his family for three generations, 2. the dirt never hard pans, 3. the dirt never crusts, 4. he does not add chemicals to this field, 5. it out produces the balance of his acres which do receive chemical fertilizers. Just so happens native Americans occupied this property.
What is in this dirt to make it so black? We will know after it has been anylized.
P.S. I am working on this project with a close friend who has a degree in chemistry and my daughter who has a masters in bio-chemistry.

Pagardner! You're a real person! Posting a real followup on your own thread! Thank you. :) You have restored my faith in humanity.

We do see people dropping by here on this forum (and other GW forums) and making their first post on the same day they register. Which is fine, but... whenever said first post immediately promotes the wonders of some organic product for sale, it makes some of us kinda cynical about the motives of the new poster. Hence, my replies above.

As well, intelligent discussions do take place here. There are a number of them on this forum (and on Soil, Compost & Mulch, and other forums here) about the use of charcoal in soil. I'll try a search and demonstrate the results at the link, below.

Welcome to the GardenWeb forums, Pagardner. :)

All the best,
-Patrick

Here is a link that might be useful: Google search for 'terra preta' on GardenWeb

"Then again many ag schools have trouble replicating the success that organic and holistic farmers have, too."
Keeping in mind that the people that "discovered" terra preta were soil scientists and horticulturists employed by many of the Ag Schools that have trouble replicating the success of organic gardeners and farmers.

Kimm, perhaps you might find a search on the subject of "terra petra" interesting. In addition I would add that archeaologists are now able to tap into GIS programs that have identified and mapped soils of the earth. It helps them to locate terra preta soils which the ancients recognized to be fertile lands for crop growing. With this knowlege archeaologists have located potential sites to explore, excavate and trace the routes of our early ancestors.

I have read just about everything I can find about "Terra Preta" and those soil scientists that I correspond with, in many parts of this world, are organic gardeners and understand organic farming, and a couple even teach these principles (organic) at the universities they are employed by. None of them have been able to replicate what happened at the original research site, in Israel, in Ireland, in Illinois, in North Carolina, in New Zeland.

Here's an overview article on Terra Preta from Nature, published in August 2006:

Black Is The New Green

As they note, soil scientists at Cornell University in the USA and at the University of Bayreuth in Germany have been studying Terra Preta for some time. Among other researchers on other continents.

Cornell website on Terra Preta

Terra Preta Web Site at the University of Bayreuth

Another article published in May 2007 in Scientific American, specific to biochar but also discussing Terra Preta:

Special Report: Inspired by Ancient Amazonians, a Plan to Convert Trash into Environmental Treasure

All the best,
-Patrick

Terra Preta is an interesting subject. On the web I find lots of verbiage on it's fertility, history, and high carbon (black carbon, whatever that might be).

What's missing are the hard facts. What are the various percentages of course sand, medium sand, find sand, course silt, fine silt, and clay? What are the minerals that make up the factions? PH? CEC, and is it high due to hydrocarbons or clay or both? How do the above compare to non- Preta soils nearby or with other Terra Preta soils at a distant location?

What I find on the net are commercial sites that know all the secrets of Terra Preta and have just the product to re-create the effect in your soil. Right.

Then there are those sites like the University of Bayreuth linked above. Go there and on the front page you will find a couple of photos distinguishing Terra Preta soils from Oxisol (a nearby soil type?). The soil profiles have been "Photoshoped". Makes me wonder if the rest of their facts have also been tinkered with.

Gentlemen, while I applaud the application of a careful and sceptical frame of mind to science -- especially in relatively new areas of science, like Terra Preta or cold fusion -- your criticisms expressed above are themselves scientifically unfounded. And I'm highly sceptical myself, about the various points you raise. From a scientific point of view.

Kimmsr, stating you have correspondants who have told you they could not replicate the experiments of others who have investigated Terra Preta -- proves nothing, scientifically.

Where are their studies? Where are the links to their published experiments? In short: where's their science?

I have correspondants and friends who think and believe all kinds of things. (A guy I know firmly believes he's the living reincarnation of Elvis Presley, for one example.) Yet it proves nothing -- scientifically -- to state "my friends think or believe X, Y, or Z."

Pls8xx, I've read hard science about Terra Preta on the net. Published scientific experiments done by scientists. They're out there. I'd suggest you start by following the links I've posted, you'll likely soon find them.

Whether they answer your questions or not, is entirely another issue. However, it's inherent in the nature of science that it raises more questions than it answers -- a well-known problem with the scientific method itself, when examined from a philosophical point of view.

This problem is especially obvious in relatively new areas of investigation in science. From my reading, serious scientific investigations into Terra Preta aren't even two decades old. Also from my reading, Terra Preta appears to be a complex and multifactorial process -- like soil itself -- which has not easily yielded up a clear and simple understanding, so far.

Finally, whether an individual photograph posted on a scientific website is (or is not) altered -- proves nothing scientifically. And while you may wonder all you please about whether this may mean the scientific results also posted on that website are altered -- your wondering also proves nothing. Scientifically.

Most of the time I enjoy most of the posts both of you write. And I welcome your sceptic inquiries.

But my welcome does not extend to giving more credit to your sceptical attitudes, than I do to published articles in Scientific American and Nature -- two of the oldest and best-known journals in science. If they take Terra Preta seriously enough to publish articles about it, I think it's worth my serious and thoughtful consideration.

Neither does my welcome of sceptical attitudes extend to dismissing what's posted on the Bayreuth or Cornell websites because somebody may have messed around with a photo, or because my online friends have told me those results can't be repeated.

Please don't misunderstand me: I don't believe or disbelieve in Terra Preta. There is some compelling evidence it works, in situ, where it was discovered. I've read some hard science which has indicated those positive results have been replicated in laboratory studies. And, there are also serious questions.

But I don't have a dog in this fight. I'm not using charcoal or biochar of any kind in my garden. I'm not advocating for the use of it. Neither am I saying it totally sucks dude, and no real gardener with half a brain in their head should like ever take it seriously, really.

I am advocating for thoughtful and serious consideration of Terra Preta -- until it's been thoroughly investigated. Whether it will be 100% proven a miraculous wundersoil, or debunked as a total fraud still remains (in my opinion) an open question at this point.

And until someone provides solid scientific advice to convince me -- one way or the other -- my mind will continue to remain open on this subject.

I posted the links above so others on this forum could learn about Terra Preta. I invite people to do so, and to make up their own minds. And if there is more recent science anyone can provide -- either for, or against Terra Preta -- please do provide it. We're all of us here to learn, I hope.

All the best,
-Patrick

Charcoal,could be something I would call organic material. It once was green and growing, IE a tree. Here lies the but, its a processed OM, but not naturally. One must find out how much nonrenewable resources were used in the making. Since I use propane to cook with[the BBQ] I can't imagine the cost per pound of charcoal. Processed items cost.
I feel we have used a lot of broadband to say not much about charcoal.
I take my tree and brush trimmings cut them small pieces and pile them til punky, then crush them into the compost pile.
Conifer trimming go back under the trees they came from.

One could argue the point that charcoal is totally inert, totally sterile, and of no use in a living soil, such as organic gardeners have.
At least one doesn't have compost it. It has all ready been done, overly.
Bryan

I've used waste activated charcoal from large home water filters (about pool filter size) to amend hard clay. The charcoal was slightly contaminated with gasoline (why the water was being filtered) but I understand what happens to that sort of contaminant in a soil environment and it did not concern me. It worked well. I wish I could get a ton of the stuff.

Bryan, by cost to process charcoal do you mean actual money spent, or cost in terms of material used or smoke produced or what? We have a May Day bonfire every year (well, except that year it rained so much, then we had a fire in the wood stove.) We only burn branches, dried weeds, bark, and wood too punky for the wood stove. No cost there, it is all waste product. Light it with some matches and a couple sheets of newspaper. When the party is over, we douse it with water. In the morning, viola', lots of free charcoal. No cost to me (although I did have a hangover) so I am sprinkling some into some garden beds. I suppose I should do something scientific and add it to part of one bed and not the other part.

Marcia

Thank you. The last time I visited this forum I had washed my hands of it never to return. The above discussion was what I was looking for, intelligent scepticism and debate. I too was scepticle of the idea until I visited with a local farmer who has this special field that I have mentioned in an earlier reply.
Recently I purchased a tri-axle load of red clay for a small raised bed garden. Last year it was fed : about 500 lbs of coffee grounds and about 40 5 gallon buckets of egg shells from my favorite diner, grass clippings, wood chips, all the maple leaves from the yard, cow manure well aged, peat moss, shredded weathered newspaper, and 200 lbs of lime and gypsum. In the fall it received winter rye for a cover.
This year it is dark brown, has a fair amount of worms, but is still somewhat pastey and has mostly marble sized particles. This year it is growing sweet corn, stringbeans, limas, peas, lettus of all types, and some weeds. So far no chemicals. I can tell you that getting to this point is a Lot of Work and Time. Maybe charcoal is the answer, maybe not in total, but as a good start. Let' find out.
Thanks again. Best regards to all.

Marcia,
I love this place. The only place I go where one needs a disclaimer. Here, it's like grammar, i before e except after c,... Vowels are, a e i o u and sometimes y.
I shuda put at the end I could be wrong.
In your case I was.
I was only thinking of someone buying a inert sterile product to put into living soil.
I could be wrong!!!
Bryan

I have started a FAQ related to biochar and gardening. Perhaps you know: What are the frequently asked questions that gardeners need to know. For me it was How do I make charcoal without smoking out my neighbors? What is the application rate? How do you prevent stalling? (A. run it through the compost) What are the effects? How long does it take for the effects to express themselves?

I am a soil scientist (and no I don't sell products or services related to biochar) but this FAQ is in no way meant to plumb the depths of pedological and edaphological knowledge on the subject. It is meant to give folks the basic reference points to get folks oriented and started down the path to figuring out if there is anything of practical value as it applies to their personal garden space.

We know that some effects from adding charcoal are nearly instantaneous, like the increase in potassium and the liming effect related to the ash component of the biochar. That's the boring stuff.

It is the informed suspicion of soil scientists working on terra preta that it really isn't the charcoal, its the biology, that produces the most intriguing effects, the ones that haven't been figured out yet. For instance, we deduce that it is the biology that provides a patina of organic constituents that serve to increase soil CEC.

We know simple facts, such as that the bio-oil condensate component, when present, can stimulate microbial respiration and cause a a marked increase in biomass. Biomass stimulation occurs with compost also, but it is erroneous to conclude that charcoal can somehow replace compost as a soil additive. If anything charcoal use encourages the use of compost, in that the mineral and biological decomposition products from compost appear to marry well with charcoal.

In many parts of the world, thanks to the indigenous use of fire to manage the land, our native soils have 10-30% of their organic carbon as black carbon. So in many ways soil biology has already been primed to adapt to increased charcoal in the soil environment. What will happen when I add charcoal to my garden soil? Something good I feel certain, and I hope you all will join me in finding out. For me, biochar is already a vehicle of substantial personal change in my gardening habits, one that has me bringing ever increasing volumes of waste materials (and my neighbors waste materials) into the compost pile. If our experience with reduced tillage agriculture is any indication, it can take many years for soil biology to come into its own when we shift to promoting more soil biology. It could take decades in the case of charcoal. My grandchildren may see the real treasure I am cultivating in my soil, but I may be long gone by then. For me, being encouraged to transform my personal habits in utilizing the waste that would normally get away, this is more than enough encouragement for me.

Here is a link that might be useful: Gardening with Biochar

Good discussion. Here is some of my own early findings with charcoal. My test began with a 6 pk of First Lady tomatoes. Everybody grows tomatoes. Each plant was separately planted into a 5 gallon container using ordinary top soil from a pile located at another property that has not been used in over twenty years. It tested slightly acidic, expected from acid rain, and low in other nutrients. Perfect.
One tomato received only topsoil, my baseline, two tomatoes received the common chemicals used today, two received charcoal amendments without any chemical enhancements, and one received something that I cannot tell you about just yet.
Findings. The charcoal enhanced tomato greened up the quickest and grew to reach the top of the pot first. Second the chemical fed toms followed by the others. All have deveoped nice flower buds at this time and reach two inches above the containers.
The tomato in raw dirt is currently slightly less green than the others. Probably indicating future issues with the plant.
Initially all received collected rain water and were watered on the same day in a measured equal amount. It did not take to long to notice that the charcoal tom did not need or want all that water. It now gets watered every other cycle and may stil be to much.
Other findings are that my other transplants like cucs, cantalopes, brocolli, and others received charcaol ammendments and quickly adapted to the earth, no shock usually associated with transplants.
In short, I believe that charcoal acts like a nutrient rich sponge giving to the earth and plants for years to come. Goodby peat and pearlite. I will still compost. As stated above our children may reap the ultimate benefit of our work with charcoal and other more natural ammendments. Best regards to all.

What is meant by charcoal? Over the years my wife has taken every ounce of charcoal from wood burned in our fire pit (probably 15 gallons per year) and tossed it on her garden. It doesn't grow much well. It has raised the native pH (6.8) to 7.9.

What is the point? Are we talking about a different charcoal?

Justaguy2:

Soil scientist Christof Steiner measured an 880% increase in yield for fertilizer+charcoal in comparison with fertilizer alone on lateritic soils in the Amazon. In the video (see link) it looks like quinoa, but being European, CS refers to it with the term "corn", meaning grain.

More exciting than CS' yield response is that, although his charcoal+fertilizer plots had higher yield and more mineral nutrients were removed from the soil during the 4 year study, soil levels of these nutrients were depressed less in the char+fert amended plots than in the fertilizer only plots. The combination of decreased leaching and increased mineralization that would account for this points to a unlocked biological potential that transcends the simple physical and chemical effects one would expect from adding simple elemental, inert black carbon.

Very exciting that. However, used thoughtlessly, charcoal can impair crop yield.

As Steiner and many others have demonstrated, using fresh charcoal alone will reduce yield/biomass production for the first season or two unless soil is pretty healthy to start with. Steiner was aware of this when he designed his study. This effect implies that charcoal, although inert, stimulates microbial activity, and they out-compete the plants for the limited nutrient resource. We don't have the long term studies to demonstrate that yield then recover and trend to levels of productivity that exceed pre-amendment levels, but we suspect improved productivity will likely be the longer term norm.

Long before Steiner, the Japanese established that nodulation in legumes is stimulated in the presence of charcoal. As such, combining charcoal amendments with leguminous green manure rotation could prove to be an important tool for gardeners the world over.

The ash component of charcoal has an effective pH of 12-13. Certainly this accounts for the effect you have seen in your soil. I anticipate that the black carbon portion of charcoal itself, in isolation from the ash, has no liming effect.

The porous structure of charcoal is observed to utilized by plant roots, fungal hyphae, and colonized by archaea and bacteria. Theoretically quite inert, the structure of charcoal seems to stimulate soil life in a way reminiscent of marine reef structures.

Here is a link that might be useful: The Secret of El Dorado

Charcoal, as noted above, is inert but could help aeration and give roots a boost. Ashes do add to the soil things that grow plants well As a plant food, ashes contain 5 to 7 percent potassium and 11/2 to 2 percent phosphorous. They also have 25 to 50 percent calcium compounds. Hardwood (e.g. oak) ashes contain more potassium than those from softwoods (e.g. pine). If left out in the rain, because these nutrients are water-soluble, the ashes will lose their nutritive value. The less soluble carbonates which cause alkalinity will remain longer. So, maybe we are discussing ashes here.

"In short, I believe that charcoal acts like a nutrient rich sponge giving to the earth and plants for years to come. Goodby peat and pearlite."

Hey Pagardener, do you believe that charcoal is stable and absorbent enough to replace such sterile soil amendments like perlite or vermiculite?

I believe that we have only touched the tip of the iceberg on charcoal. My personal doctor is also a gardener so during check ups we chat about gardening and alternative medicine. Turns out charcoal is a remedy for some poisons and a detox for heavy metal ingestion. He gave no specifics, I guess to save his license. Anyway, if charcoal is sterile enough for human ingestion, then I would guess it to be as sterile or more so than perlite and vermiculite. At least the possibility for asbestos should not be there. I have not tried or seen any reports of starting seeds in just charcoal. I will try that one this spring. Let me close by stating that charcoal, terra preta, is part of a total gardening package as others above have stated too. Could peat, perlite, and vermiculite be a part of the package? I do not see why not. How 'bout peat carcoal mix as a starter? We've only just begun in my opinion. Best regards to all.

My orchid plant is now blooming. It has 7 stalks of blooms and buds. Guess what? It has charcoal in the "soil" mix.

Science teacher going to have students do a comparitive experiment using tomatoes grown indoors under grow lights. Comparing total mass of tomatoes grown in clay-based soil TO total mass of tomatoes grown in clay-based soil with BioChar. I plan on fertilizing, BUT only organic fertilizers. One issue I may face is that charcoal is basic and most veggies like MILDLY acidic soil. We are going to start from seeds so I don't expect results soon.

By the way, ash is different from charcoal. The remains of a wood fire provide a mixture of the two.

Wayne, did you innoculate your charcoal with anything before hand? Did you mix it with anything?

To those of you who have used charcoal/biochar in beds or pots: what ratio of charcoal to other soil components are you using?

I make my own charcoal (for grilling) from oak and have plenty of particles too small to use in the grill. I've been sprinkling some in beds and around fruit trees. I expect that the amounts are insignificant.

Here is a link that might be useful: my blog (with entries on making charcoal)

Amazon soils are overly acidic, very nutrient poor soils. If you did anything to add orgainc matereal to it, it will raise the pH and would slow down the leaching of minerals. Charcoal breaks down less slowly than compost, so it's sterility and pH buffering may be key to it's effects in an otherwise incomparable soil. I'll say it for now, it isn't a good idea to put charcoal in a soil with a proper pH for plant growth, the vast majority of soils. As a biologist, I can palpate the mysticism on these types of threads, I can almost smell the manure, I can certainly see the sensationalism and voodoo factorings going on here. Once the greenies got involved with the whole carbon sequestration into the soil novelty, did it become touted as frontier science. People are emotionally involved, and that's a sell sign. Sell! Unload that hot stock, brother.

Charcoal itself is basically inert. Yet it annoys radiochemists doing carbon-14 dating because roots invade it. They are looking for potassium ions (K+), which tend to stick to electron-rich saturated ring structures in charcoal. Like zeolites and diatomaceous earth, charcoal lightens soil structure, traps nutrients (and water), keeps them from leaching away, and hangs around. It may take a year or 2 to come to equilibrium with the soil, which may acount for some reproducibility problems.

Charcoal _ash_ is a different matter. Very high pH (basically--no pun intended--it is Na2O and K2O, which become KOH and NaOH--lye--when they meet water). It is best put in the compost bin for a year, where the bases (anything with OH-) can react with acids (forming salts) or lipid acids (forming soaps), or generally get attached to the large indeterminate organic molecules of humic acid.

'Activated' charcoal has been heated to drive out all the things that like to stick to it. (WW I gas masks had charcoal filters, because the poison gasses of the day stuck to it well.) _Any_ charcoal in soil will gradually equilibrate and store nutrients; the activated variety just does it faster. Roots are chemical specialists at taking nutrients away from other things. (But they can't take phosphate from iron phosphate, for instance--which leads citrus growers with iron-rich soils to use foliar phosphate fertilizer sprayed from airplanes.) Charcoal doesn't hang on to things the way iron can.

Mind you, the above is just high-school chemistry. I am on my way to buy a bag of supermarket briquettes, batter them into BB-sized bits, and see if they improve my 30%-clay soil.

Ferren I would discourage you from spending your money on briquettes, because they are composed of a high percentage of clay. You should be able to buy bagged true charcoal at a hardware store or a market that caters to the Hispanic community. The cost is about the same.

I have made bio-char with a charcoal chimney. I then soak the char in water for weeks to get it a perfect ph and it also takes out all nutrients making the perfect perlite replacement!

Using it in ground can make great places to live for microorganisms and store nutrients, air, filter, ect.. As far as "slash and burn", that is a common practice.

A funny story- Farmers where using ash on fields and some manure. Scientists came and tested the soil to find a 8+ ph with crops growing perfect. The natural buffering of nature at it's best. :)

Where can we learn about this idea of natural buffering? Does it also work for the other end of the pH scale?

Yes I am glad you asked. It does in fact. Picture how LITTLE ph buffering growing hydroponically in rockwool or even coco. On the other side of the scale- hydroponics have very little ph buffer at all. Needing 6.7-7.5 to thrive. On the other end of the scale- a soil full of organic material like compost will will have a HUGE buffer. Plants can still uptake nutrients whether ph is 6 or 8. A reason that proper soil management- mulching with organic material will ensure a long term health of the soil. A reason a small farm or gardener really never needs to get a soil test. If the soil already was tested once or the native soil was already good, it does not make much sense to try to see what is needed becasue the smaller farm or garden will not really need to save that little fertilizer. I have only one all purpose fertilizer, then I use OM to add every year. A soil test would do NOTHING for me as I am still going to use the SAME all purpose fertilizer when plants need to be fertilized. I grow the same crop year after in the same rows with no soil tests. I just add a slow release fertilizer with every need micro and macronutrient so I know the plant will grow. I use a little leaf compost to keep good soil management and the ph buffering we talked about.

Thank-you for responding. What about blueberries? Does OM buffering allow those acid loving plants to thrive at closer to nuetral pH?

Plants growing in soils outside the pH range they have evolved to grow in will be subject to more insect pest and plant disease problems then plants growing in soils they have learned to grow in. A soil pH out of range limits the nutrients available to that plant. A soil with not enough or an otherwise unbalanced nutrient level will be more attractive to insect pests and more susceptible to plant diseases. Even "conventional" growers recognize the need for a proper soil pH and commercial growers have soil testing done so they do not spend money on nutrients they do not need.
Blueberries can grow in soils with a pH close to neutral but they will not thrive.

The master gardener makes a very good point often misunderstood and ignored. In very healthy soils, say 5%om and higher ph is essentially irrelevant. The cat ion exchange capacity is what determines the availability to plants of nutrients. A cation (+) (pron.: /ˈk�t.aɪ.ən/ KAT-eye-ən), from the Greek word κατά (kat�), meaning "down", is an ion with fewer electrons than protons, giving it a positive charge. The positive ions are to simplify things "open to" or hunting for negatively charged particles. In soils the desirable negatively charged particles are the nutrients, these will chemically bond with the cat ions. The higher the organic matter, the higher the cat ion capacity of a soil, and the higher its ability to keep or maintain the nutrients in the root strata. With high organic matter soils pH becomes irrelevant because there is so much nutrient available at basically any pH that the plants will not have any lack of access and availability therein. Organic matter may be very low in plant nutrients, such as peat moss. Or organic matter may be very high in plant nutrients, such as compost and manures. So then determining factors in soil science regarding high organic soils is not pH, but, is there sufficient NPK etc. bonded to the cat ions?

Masbustelo,

Yes, we are on the same page. This is a point I try to make very much. This is why a rich potting mix will have a better ph buffer than a light soilless mix.

Thanks for the information, I will continue adding OM and sulfur w/iron to the Blueberries. I didn't do either last season, so I imagine that the soils are now closer to neutral pH and the CEC has been diminished also.

There are two awesome books on this subject by Leonard Ridzon. The Carbon Cycle and the Carbon Connection. Unfortunately I've lost my contact for the Nutricarb product that he produced. You could add an inch of topsoil a year with it Fascinating books.