Can Plants Grow in Straight Charcoal? Biochar Experiments 

Awesome experiments 👍 Many plant collectors in the tropics grow in pure charcoal since most other substrates either decompose too quickly or hold too much moisture. One thing I’ve read in regards to orchid culture in pure charcoal is that water purity is important to avoid salt buildup. Edit: you’re right, charcoal is superior in its ability to harbor microbial life as well as mycorrhizal fugi- even compared to high surface area mineral substrates like pumice, perlite, etc

This popped up in my YT feed and I’m mesmerized by how well that pepper plant did. I wonder if a top dressing of a rich compost would both a. Help hold moisture and b. Release nutrients each time it was watered. I’m going to try this next year with a few plants. Thanks for the great content!

wow ... interesting experiment ... Thank you .. The pepper plants leaves looks great Have a good evening

Hi Steven. Would it possible for a 'homestead tour' type video. I'd like to see an overview of your site. I'm sure it would be popular with others too.

I think I know why some of your plants had some calcium deficiency and, possibly, deficiency of other nutrients like iron, as indicated by the yellowing: there is nothing wrong with charcoal in and of itself. Charcoal is an excellent addition to substrates. It has a high Cation Exchange Capacity (CEC), meaning that it should be able to retain nutrients supplied by inorganic and organic fertilisers, and supply these nutrients to the plant roots at a steady rate. You want something with a high CEC (e.g. charcoal, coir, peat, vermiculite, a pinch of loamy garden soil) in your potting mix, as it means you'd not have to fertilise your potted plants so often. With that being said, charcoal tends to contain varying traces of potassium carbonate (potash), which is a main constituent of wood ash. The issue is that potassium carbonate (potash), while being a good source of potassium, is that it is strongly alkaline, and it reacts with water-soluble compounds of calcium, iron, magnesium, manganese, copper, zinc, etc, to render them insoluble (as the carbonate salts). Insoluble compounds cannot be taken up by the plant's roots. When using charcoal, it is a good idea to pre-treat in an acid, such as vinegar (which is, for all intents and purposes, dilute acetic acid), citric acid, dilute phosphoric acid or dilute nitric acid, to neutralise the alkalinity caused by the traces of potash. Alternatively, simply flush-out the alkalinity with lots of water, then check the pH to see of it is still alkaline (above pH 7.5). You can check the pH by making a slurry of the charcoal (or any growing substrate, for that matter) in water, then dip the end of a digital pH probe into the slurry. A pH value of 6.0 - 6.5 is ideal for many plant species. The digital display pH probes are very accurate and I highly reccomend them.

Thanks Steven. Just over two decades ago I was in Indonesia working in a vegetable growing project. we had also a quite large greenhouse where we grew different vegetables (tomatoes, peppers, cucumbers, melon,...) in polybags filled with charred rice husks. We had a computerized dripping installation so we were able to give a balanced supply of all the needed elements and got good results. If you use solely biochar don't forget to add the micro nutrients that normally is provided by the soil. I'm making charcoal in my stove for the moment using the heat too!

Definitely an interesting test.

That was a great video. Here's what I'd always remember about charcoal. If I was going to set a wooden fence I would charcoal the butt and that fence posts will last forever.

roots dont go deep in pepper, si normal. Nice experiment!!! congratulations

When I did Aquaponics we had grow beds if just cinders. I tried some with just biochar and worked similarly. Both are just the substrate and give microorganisms a place to do their thing in moving nutrients to and from plants. Since I didn't use a biofilter to take out the bigger stuff, it eventually would clog the biochar faster than the biology could keep up with it. Hoping to do some greenhouse tests with biochar and compost, just for the heck of it.

I would be interested in seeing a video of how the biochar would work just as a ground cover, to see if it would work like wood chips do in the Back To Eden gardening method. Maybe try it on some of your perennial plants or fruit trees.

I'm glad your recording your experiments. Dr Mercola just interviewed Albert Bateson his book called Burn ( a biochar industrial revolution) . Biochar adds shear strength to concrete and blocks emfs. Just thought I'd add to the uses. I advocate for backyard char and gardens regardless of who hob knobs about the next revolution.

As another commentor suggested, biochar does not provide all of the nutrients a plant needs, lacking phosphorus and potassium. I make bonechar amongst my regular biochar to supplement calcium and phosphorus, whilst also adding dried banana peels to the fire to make my new-fangled banana biochar for the addition of potassium. With this mix I am capable of growing some specific plants in my straight biochar.

I'm so happy I found your videos. Great to see someone testing and analyzing their methods in the garden. Cheers man!

This summer i grow appletree with gravel + charcoal. In control i got grow 40 centimeter in hight my appletree. With gravel and biochar i got 80 centimeters. It is in Siberia where very short summer. Next summer i will try grow in pure biochar but in pit not pot.

Thanks for sharing. For your graywater treatment I would recommend growing bamboo in it. Bamboo roots are known for their biological activity and has been used in water treatment for quite some time.

Did three charcoal pits and filled them in place myself. Filled with leaves, mulch, coffee grounds, and house scraps. Some tanning "waste" too. Hoping to grow peppers, but probably N fixing cowpeas will do best. Nice too see how well that pepper did. Really interesting stuff.

FANTASTIC EXPERIMENT!! Co-composting biochar study from University of Minnesota shows tremendous influence on nutrient loads and retention. I can send a link if interested!

I think it was Idaho the soil is 42% natural biochar. Charcoal will suck up all the nutrients at first hence very good in tropical soils You need to load it up with nutrients first. I an going to use food waste on my balcony garden.

Thank you for sending me that cactus! I was wondering why the roots had charcoal on them. I heard charcoal is good to prevent root rot.

Very well explained. I have done it on bell pepper. It did great. Now i am trying it on tomatoes.

Awesome experiment thank you for sharing. One thing you sort of did not mention was a a bit of a comparison between these amazing results you got with straight charcoal and well aged and saturated inoculated charcoal (biochar)results. I know you have covered it in another video in a slightly different context, a really interesting addition to this test would be using aged precharged charcoal it another pot to compare. On our garden plot we have noticed the difference over time. We have 18" deep raised beds filled with compost perlite and top soil amended with rock dust .We applied 1 pound per square foot of pre inoculated (soaked in a trash barrel full of urine water and humic acid for a week, I also adjusted the ph with vinegar and buffered with rock dust while it soaked) . Anyway the soil we treated with the char was already fertile before we started (10 foot tall tomato plants) and used as mixed veggie beds. (Yes we are ocd tinkering fools that just cant stop) Our results and conclusions based on anecdotal evidence, that we observed in our garden in the northeast over 4 years after gardening the same space/soil for 6 years previous. First year: growth was noticeably smaller than anything before but we had expected this and foolishly thought aggressive precharging the charcoal would offset it more than it did. We had somewhat stunted plants with fair production . Second year: Soil analysis from umas extension reported everything way to high and over fertilized. We added nothing . Plant growth was average but had no problems and so was yield.(this is remarkable to me it shows that the char is actually storing nutrients ) Third year: Still test really high over fertilized except report possible slight nitrogen deficiency, we add alfalfa pellets. Plant growth starts to really show some vigor and production is finally better than before the bio char addition. Yields are up. Fourth year: Still only need to add nitrogen! we use some alfalfa pellets, compost, a dab of blood meal and we planted very late lost 25 percent of our normal growing season. This was the best production of 10 years gardening the space. A 47 pound winter melons which you need to try if you do not already know about them......and hundreds of pounds more produce, arugula cut and cut and cut again 15 lbs of out of a 3x5 section..... all this out of our 4x40 foot bed, planted late. My point , yes you can use the charcoal right away but the payoff is really in the long term as the char is colonized by soil organisms and and it absorbs nutrients and mixes into the soil when this happens the whole system just dramatically works much better, the plants seem to have better access to what they need. I also agree if you have the space to share for a nearly fallow bed, put the char right into the soils you will grow in and let it charge, balance, build and whatever else it does for the next season.(we only have 160 square feet of total yard growing space so a bit of a precharge makes more sense, for us.) Biochar does work, even on already fertile soil and does give results but you need to think about your application and give it time, and patience , to get the optimal results. This is not "plug and play" instant results but it could be "dump and chillout" Ps. Ok so i might get roasted for not making my own charcoal... but i am on a tiny lot in a very urban area it is not practical to build a bonfire ect. SO the first year we crushed 150 pounds of hardwood lump charcoal by hand with 2x4 s that experience really sucked and some family members still resent the experience. Out of desperation I found Granulated hardwood charcoal to the rescue in 60 lb bags...much cheaper than pre made over priced "biochar" and you don't get bloody hands crushing it! If you are on the east coast this is were we get it. humphrey-charcoal.com/home.html . and also try just adding a small layer of granulated charcoal to the bottom of that stinky nasty kitchen compost bucket you have every time you dump it into the main compost. Your kitchen will not stink nearly as much, and you will be adding inoculated biochar to your soil every time you use the finished compost (i also spray mine with em1) . they already put charcoal into orchid mix.... I hope this helps someone, Skillcult rocks! Have a great day! Shane

Yes that was very interesting. Gives me some ideas of what to do with all that charcoal I accumulated, since I have yet to find a feasible way of crushing it - so mixing it with some compost and using it in pots or raised beds, uncrushed, and reusing it makes sense. I wonder if it's any different to normal soil in the aspect of crop rotation... does it keep pathogens longer as it does nutrients, or maybe, hopefully, the other way around. Only one way to find out I guess. Thanks! Nimrod

For plant research the ideal hydroponic substrate is fully neutral, like plastic or glass beads, this allows full control and reduces variables. In commercial growing some ion exchange is acceptable, too much will unbalance the nutrient formulas at least in the short term. Big operations can do the analysis needed to compensate the nutrient mix for the substrate, for example BC hothouse that does large scale tomato and cucumbers is known to use wood chips but they need to adjust for the nitrogen tie-up. The ion exchange capacity of char varies widely, both in total exchange sites and in anions verses cations,(positive or negative surface charges) so it would be hard to predict without some controls over the many production variables. Vermiculite has a high cation exchange capacity(and high water retention), perlite has no exchange(but good water retention), sand and silt have very little CEC but some source minerals can leach and disrupt pH, bentonite clays have extremely high CEC. (vermiculite is made from a clay-related mineral. Cat litters are often made from bentonite, and so can be a source for modest amounts of the clay if you can get a cheap brand with no perfumes and antibacterials. Sodium bentonite has greater reaction with water than calcium bentonite [the Na and Ca are part of the structures not available to plants])

I've noticed if you keep fertilizing regularly(weekly) then the roots won't go deeper instead the start spreading horizontally. You can always layer compost seperately on the base of the pot incase the added fertilizer isn't ehough the roots will dig deep in search for extra neutrition.

Sir, thanks a lot but i dont have activated charcoal, ican i use normal charcoal. Also i wanna know if i gitta clean the powder or can i keep the powder in the mix

Thanks Steven. I was wondering how your experiments with charcoal were going. As a person who grows dwarf trees in containers (because I rent so if I need to move I can take my 'orchard' with me), growing media interests me greatly. I'm thinking of setting up a small retort to make some charcoal but have been waiting for your results. :) I used to use (activated) charcoal in another life when I was responsible for semi-closed aquatic environments and was fascinated by its ability to adsorb various chemicals. When it's used in that situation however you have to be careful as it reaches it 'tipping point' where it's adsorbed all that it can and will then dump some of the 'contents' back into the system. That can be fatal to the aquatic environment as it's such a sudden change inhabitants don't get time to acclimate. Because of that I've always been wary of using it for growing, at least in high concentrations. However in the aquatic situation the char was always flooded so I'm not sure if that would ever occur when using char in a growing media.

i had some problems with my turmeric not growing without pre-charging my charcoal.

Your pepper plant is pretty good size for the pot you have it in and the variety. Pepper plant size (relative to the strain) is mostly determined by the size of the container they grow in. I have experimented with container sizes and find that 2.5 gallon is a half size plant, 5 gallon is two thirds, and in the ground unrestricted is a full size pepper plant. Restricting the roots is crucial if you have a short growing period like the PNW. Some strains of peppers will wait until they are "full size" if unrestricted and will flower too late to get a decent second harvest before frost. By putting it in a container the plant will grow to it's maximum size for the given volume earlier in the season and begin to flower earlier. Sometimes a small plant with two strong flushes will out produce a big plant that flowers late.

Seems to me the charcoal makes a pretty good substrate. Next time you could try adding some compost for added nutrients and water retention; but all in all it's looking good.

Thanks for the update! It definitely is a neat experiment! I am experimenting with charcoal per your recomendations and I am pretty convinced ot works great! I have about 50 gallons of it ready for next year’s garden. Looking forward to it! Cool thumbnail btw!

Great experiment, we have started throwing a lot of charcoal in our chicken run to “pre-charge” the charcoal and also keep the chicken run smelling clean. I don’t think that charging the charcoal is strictly necessary as long as you are aware of it and add fertilizer when planting. The problems seem to arise when you just throw the charcoal into the soil and don’t change how you are fertilizing.

hey a hello to France, i love your technic and your philosophie, i am a permaculteur and it"s work verry well gardenning with charcoal!! thank's you for all your video and see you soon!!!

What an interesting experiment. Once again i learned something. Thank you 👍👏

Charcoal and Gravel should work great... I use egg shells for slow release calcium it works very well

Nice vid. Would be awesome if you did 5 test pots with different methods to see what works best!

I'm going to plant sameway, thank you for sharing 🙏😊

Seems like it would be great for areas with a lot of rain like in Seattle, or to fix clay soil if you dont have or dont want to use sand. I wouldnt use it on top in very sunny areas if you have any concern of mulch fires.

Thanks for the help

Thank you for sharing your knowledge.

very interesting experience

I'd been thinking that cutting diseased or cankered fruit tree material and using the trench burn method to dispose of it (so, not spreading the problem) would be quite a reasonable thing to do on many different scales of operations. That takes a problem and turns it into a resource. I also think the trench method starts the charcoal's exposure to soil microbes as soon as you drench it with water to put out the fire. It's not the same as burning it in a steel can under low oxygen conditions and producing a sterile medium,. The trench is outside in the weather, gradually exposed to the deeper layers of dirt around the pit - say, a foot to two feet deeper away from the open flames, all around the side and bottom. Kicking in some good compost after the burn would really activate the worms and microbugs too,

try planting sunflowers in straight charcoal, it has a deep taproot so it might fulfill the container that it grows in and add legume like beans under sunflower in same container and analyze what root systems look like

Thanks for the update.

Ooh, that's nice to see tested elsewhere. You might omit the fertilizer, by growing legumes first (fixes the nitrogen issue), then mix the plant in the same charsoil, and then grow something else. Currently did peas with and without a 50-50 ratio of coffee grounds, then grew onions. The pure coalsoil was tried later, so I haven't gotten to do the oniontest, but I can assume success with some crops with the right iterate process.... Charge as one grow

I've never heard of lithops before, but after seeing some photos, I think I feel a big geek-out coming on. Great experiment. I'm surprised about the shallow roots.

Maybe try half soil/compost and half charcoal.

Great experiment

did you catch the runoff from each watering session ? use that combined 50/50 with fresh water to re-apply onto the biochar , completing a charging and nutrient replenishing cycle. harvest some fresh water algae , dried out and powdered to sprinkle onto the mix.

That's what you get if you do not charge your biochar first ! Thanks to share your experiences !

Great experiment bro. I work in a wastewater lab and really want to try and see what charcoal can do with wastewater sludge since its a fairly slow composter..

What about biochar in aquaponics? Fish waste charges the char? Char can be free instead of paying for Hydroton etc. Any thoughts?

First started making char in December 21. Started storing in 30-36” plastic pipe scraps from work. About 18” tall. Saw weeds develop and get really tall this spring. No nutrients added, no other media, just homemade charcoal growing weeds with 6”+ roots into the bins of char. I’ve been thinking of starting aquaponics using raw char instead of lava rocks, the clay marbles or the shale stuff. If I can grow weeds in straight char, why can’t it replace other, more expensive substrates in aquaponics? I make char from subdivision construction scraps, fruit tree trimmings and larger tree branches and trunks that I split. All for free. Running fish waste with other trace nutrients thru the char should produce very nice results. Anyone with insight, please comment. I’ve not yet a pot to fish in, but have the property and resources to start trying. Just recently started researching aquaponics. I planted biochar treated raised beds really late this year, but results have been PHENOMENAL. Easily catching up to non biochar ground beds planted in April-may with the ones I planted in mid June using primed biochar.

I wonder how carnivorous plants would grow in straight charcoal. I think I'm going to try it out. I have problems with mold and algae growing in my carnivorous plant pots because I keep it wet at all times to simulate bog conditions. But with non-charged charcoal, I'm hoping that the lack of nutrients will prevent growth of undesirables. And the carnivorous plant itself doesn't need nutrients from the roots, so it should thrive just fine hopefully while the charcoal can hold more water than sand. Plus I think it would look really cool having it grow in a pot of pitch black charcoal.

Nice to know cuz I heard no charcoal for cacti cuz they can't handle any organic material... I just use a sand and clay mixture but I like some charcoal in potted plants cuz it absorbs odors and I think it cleans the mixes better....

Hi. Charcoal absorbes not only negative pathogens, but also nutrients. Also the PH is up to about 12, pretty high for acid loving plants. Fact is, in general, plants like PH around 6. Charcoal absorbes but doesn't release. It loses its effects in about 2 weeks.

While about biochar, your video inadvertently helped me figure out a problem I had in my garden this year. About 50 percent of my tomatoes were lost to what I thought was some kind of fungal rot that would appear at the blossom end of the fruit. I just had my soil tested and it turned out to be both low ph (~5.3) and very low calcium. Based on what you said about blossom end rot, that seems like the culprit. Working a little powdered limestone into the garden soil shouldn't be too tough, but the 15 apple trees I planted last year might be a bit tricker. I was thinking of maybe mixing limestone dust with compost so the organic acids in there help dissolve some of the Ca and make it available to the trees. After that, top dress that mixture around the trees in a 3 foot radius, cover with geotextile and top with wood chips. To you or anyone reading, does this sound reasonable? Is there any point to top dressing biochar? I could see making some a little on the 'well done' side so that there would be plenty of ash to supply Ca and other base cations. Love the recent apple breeding review series, btw. If you get into wider distribution of scionwood, I'd definitely give some of your varieties a try.

Maybe the pepper roots stayed near the top because the biochar was possibly absorbing everything immediately, being uncharged. The plant sought out nutrients where they were most plentiful, near the top, where they were applied. Who knows.

I noticed Bermuda grass put its roots into the char. It grew over into my Char pile.

U genius sir.

This idea will work for my aquaponics really well

Probably not a good idea to plant directly in the burn trench because the soil will be incredibly alkaline from the ash, unless the charcoal was very very deep and the ash is all the way at the bottom and roots may not reach that deep.

Is it ok to plant 'snake plant' with normal charcoal only?

i dont have enough char to use fully think of a aqua-ponic system it makes for a good medium for now, i use a small percentage of it with soil and compost in raised beds, mainly bc i dont have enough compost and char those raised beds consume lot of soil, but i had been getting good results from them like you mentionned, i didnt need to charge char at all, specially with trees i just mix it in bed with compost and some rotten fruits as molace substitute and i coudnt believe i got mushrooms growing on same week in a desert climate recently i charged char with urine for a few days and mixed it wth compost and got a material that have same consistency as chicken manure used it on maize beds, i will report about the results but for now, they seems to be growing well

My understanding is it’s not just the nutrients it can hold but the microorganisms that live in it. I would think for them to live and thrive there would have to a perfect climate. If it’s too wet they drown, and die, if it’s to dry they die. Micros are whats feeding the plants. So you may be able to grow in pure biochar but just like in commercial farming the nutrients become depleted when, 1) nutrients aren’t put back and 2) when microbes can no longer thrive in it. Wet at the top and dry at the bottom or visa Versa is not a good environment. Good experiment but it makes sense to me why it would not be the ideal situation for growth……

Try inoculating your charcoal first. Don't use just straight charcoal. Add to worm bins, compost before adding to garden. Then make a video and show me the magic.

Very cool experiment. Has the Kambo treatment helped your health at all?

I charge my bio char with a chicken tractor on top of the beds.I put my char coal on a tarp in the driveway then run over it with my truck to break in up.Then i put it in my 3 beds that are 4' by 35'.Then cover with free oak chips i get from the county and some sea weed i get free from the sea.Then chicken tractor goes on and is moved every few days all year long if i am not growing something.I am about to harvest a nice crop of butternut squash. Seems to work and the price is right Free!

Subscribed just cause of this video

So it seems then, that pottery shards do play a big role in terra preta soils as they hold moisture pretty well.

My current charging method is just throwing a bunch of charcoal into my compost heap as I'm building it. Obviously the charcoal sticks around while the compost needs repeated application, so after the charcoal content looks good in my beds I'll stop composting with charcoal.

I have a theory about the charging thing but it is only theory. I am a big fan of no-till growing methods and have went almost completely zero till. The big thing that is talked about with this is to keep something growing and photosynthesizing at all times if possible in order to produce the sugars needed to keep the microbes alive. So to your point I think that until there are actually plant roots exuding long chain sugars the microbes aren't going to do their thing. So my guess is that the charge might not be so effective anyway. On a different note I am beginning to take interest in Korean Natural Farming, or at least some elements of it. I wonder if you were able to inoculate the established plant bed (with a good percentage of biochar) with indigenous microorganisms would it be a microbe power house. I may do some experimenting of my own in the future to see.

Charcoal mixed with wood chips?

Hi Steven, I would like to order some scions for next year. How do I proceed?

I usually dump my used duck water in a tote and use it to grow duckweed for the chickens/ducks and to fertilize the trees. This makes me want to try dumping a buch of charcoal in there to soak up all that nitrogen rich material to use in the raised beds🤔.

Nice crests. Most ppl are unaware that plants (most) can and do source nitrogen from the air.

Is that lophora williamsii

Your "experiment" is similar to what I've been saying to my relatives . Dig a trench and make charcoal . Dig out the first batch of charcoal and make a 2nd batch in the same trench . Leave the 2nd batch in place and use the 1st batch of charcoal directly into your compost . Then put a raised bed on top of the trench and fill it with the compost charcoal mix . Then plant directly into your new raised bed . When you harvest don't dig out your root system , just cut the stalks of the plants off at "ground" level . You should never have to fertilize at all gardening this way and if you have good ground water levels you should never even have to water it at all (typical rains should take care of all of your watering needs ). Charcoal is used as a water filter for your houses , most water filter systems have either a paper filter or a charcoal filter . So a charcoal base and then even a compost with 50 % charcoal on top of that should work wonders for a raised bed .( No one I know does this but then they all have troubles with their gardens ).Cool experiment , thanks for posting this and showing your root results .

300 views and 36 likes in an hour... Pretty good

V interesting

the one that did poor was because you crushed the charcoal up finer with more ash filling the voids.....

Crushing biochar vs Not cruching biochar, please! (I don't crush it, the roots do that for me)

Just because ash has calcium doesn't mean all of it is in bio available form. If you don't want to waste your life under a microscope provide some compost to the biochar which will introduce the life that will hopefully create enough calcium in bio available form. But nobody should grow stuff in pure biochar to begin with.

final comment for today: char should be able to replace vermiculite and perlite

no involvement in the pot industry, yeah yeah! ;)

the Maya people call this terra preta!!

charcoal hillculture

Your experiment literally proved you need to charge the biochar and you still deny that fact. Your plants were nutrient deficient because the medium lacked both nutrients and microorganisms that process them and make them bioavailable.

You need to work on your voice. And mic.