# Q on charcoal in media



## Jim Toomey (May 20, 2009)

Hi all,
I have repeatedly heard from some of the greatest growers to add charcoal to the bark/perlite mix (add your preferences of mix here) to "sweeten the mixture".

What does the addition of charcoal contribute? 

I understand that it will keep the mixture from compacting, but does have other roles in the potting mixture?

In my days in aquaculture we used charcoal/carbon to absorb organic compounds, does the charcoal we use sequester any of our fertilizer nutrients?
Thanks,
Jim T


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## Hien (May 20, 2009)

AHAB said:


> Hi all,
> I have repeatedly heard from some of the greatest growers to add charcoal to the bark/perlite mix (add your preferences of mix here) to "sweeten the mixture".
> 
> What does the addition of charcoal to the potting mixture play?
> ...



I am sure it is good for something, but one time I planted a phal seedling in pure charcoal, and it died immediately.
Was that because the charcoal size was too small?
Because it was in pure charcoal?
Because the charcoal from "Hydroponex" was not pure,?
I did not know the answer but I did not add charcoal to anything anymore unless it already came with the potting of the plants I bought.


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## SlipperKing (May 20, 2009)

You are right Jim in that the carcoal is there to absorb "toxic" compounds away from the plant. I always use it but have no solid proof that it works as it's thought to do. I know of no detailed study showing the addition of carcoal adds to the life a mix or to the health of a plant growing in it. Someone else may have one.


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## NYEric (May 20, 2009)

It works to remove materials (like a carbon filter) and it opens up the media for air flow!


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## Hera (May 20, 2009)

Is there a difference between charcoal and activated charcoal pellets used in hydroponics? The local hydroponics store has these and not regular charcoal. I tempted to try some, but wasn't sure it it would do any damage. They kind of look like black kitty litter.


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## Ray (May 20, 2009)

The degree of "activation" in horticulture charcoal is minuscule compared to truly activated charcoal, and it is all at the surface rather than throughout the particle, but it still does do some trapping of crud.

Any enhanced aeration it does is merely related to particle size and shape, and nothing related to the material itself.

One problem with charcoal is that its usefulness for absorbing and holding foul stuff also means it is pretty good at absorbing minerals, so its rate of mineral buildup is relatively significant, requiring regular repotting with fresh medium.

For what its worth, I found that phals did really well in 1/3 charcoal 2/3 sphagnum - although it was tough to mix the chunks with the strands.


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## Jim Toomey (May 20, 2009)

Thank you for your replies!

Since it does hold "stuff" there seems to be some concern about the buildup of stuff/crud and burning or inhibiting root growth.

I'm questioning because I am looking for valid reasons to add charcoal. 
There seems to be a lot of anecdotal information...

Would it be better to just add an inert material to prevent compacting, say prime agra, perlite or other inorganic material?

Thanks again,
Jim


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## orchidmaven (May 20, 2009)

I once asked Alan Moon about charcoal. His response, it was a mind set of the American Paph grower. I do not use charcoal due to cost. I know for a fact you can grow any orchid in just about any mix. I have seen the most incredible Odontoglossum grown in foam pillow stuffing. And it was spectacular! Odonts in 100% perlite, Masdevallias and Miltoniopsis in peat/perlite. I remember getting some Paphs from Stewarts Orchids years ago in chunky peat and they were stunning plants. There are as many mixes as there are growers.

As a grower I look at cost and while it is not the only criteria it figures in my calculations. Charcoal is an expensive additive that just does not perform. If it did I _might_ use it.

The performance comes with the dynamics involved in growing a particular genus. Water, fertilizer, controlling light levels through the seasons, air movement, max. and min. temperatures throughout the year, potting up to push the plants for maximum growth, etc.

Experimentation is a good thing! Just don't put all your plants into any new mix! It's not the mix, it's the dynamics.

Theresa.


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## Rick (May 21, 2009)

AHAB said:


> Since it does hold "stuff" there seems to be some concern about the buildup of stuff/crud and burning or inhibiting root growth.
> 
> I'm questioning because I am looking for valid reasons to add charcoal.
> There seems to be a lot of anecdotal information...



In the waste water biz we use activated carbon extensively (and there are many different grades with subtly different properties). It has been studied for this application extensively. 

The primary removal usage is "non-polar" organics, but many metals can be taken up by different grades of carbon too. In salt water aquaria I used it for removing copper. No activated carbon is good at pulling out fertilizer nutrients (unless they are bound to organics), and salt build up is not appreciable (we have been searching for a cost effective method of removing salts from waste water and carbon was a total failure). Once again, from waste water experience, carbon is an organic sponge, but once it is colonized with bacteria it becomes a mini waste water treatment plant on its own, as the bacteria break down the organic compounds it sequesters. Up flow fluidized bed treatment systems often use granular carbon as the support matrix for bacterial growth for this reason, and are very effective for their application.

However, as Ray mentioned, horticultural charcoal is fairly inferior to activated carbon grades for waste water use. But I use it extensively non the less (probably no more than tradition or the black box effect). Since soil matrices are "ecosystems" in their own right, I think (feel) that the microfloral buildup in carbon is ultimately beneficial to the stability of a mix. But I do also carry the concern that it has the capability of sequestering metals in some situations which could be toxic in the long run. 

Some great growers use it, but also don't know why other than "things seem to do better when they use it".


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## Ray (May 21, 2009)

Hoo boy. I hate the "things seem" reason, even if I've used it a thousand times myself!

I have noted that in old medium, charcoal seems to have a particular "feature" of building up minerals faster than other components. maybe it's just because it's black that it looks that way.


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## paphioboy (May 21, 2009)

FYI, most orchid growers in the tropics use charcoal exclusively as a medium for epiphytes, but maybe our heavy watering regime and frequent rains prevents salts from building up. but I'm a bit puzzled by Hien's phal dying. all my phals grow in charcoal very nicely. Charcoal is also used to open up soil-based mixes for terrestrials and semi-terrestrials like paphs.


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## Hien (May 21, 2009)

paphioboy said:


> FYI, most orchid growers in the tropics use charcoal exclusively as a medium for epiphytes, but maybe our heavy watering regime and frequent rains prevents salts from building up. but I'm a bit puzzled by Hien's phal dying. all my phals grow in charcoal very nicely. Charcoal is also used to open up soil-based mixes for terrestrials and semi-terrestrials like paphs.


 How big is the charcoal that you use? you plant paphs in soil?
I think maybe there were a few reasons, looking back.
-they were very small particles (less then 1/4 inch) so it may hold too much water, no air.
-I did not fertilize the plant, so there was no food, whatever minerals from the water were probably all zapped by the charcoal.


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## NYEric (May 21, 2009)

Hien, I'm almost speechless!


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## Hien (May 21, 2009)

NYEric said:


> Hien, I'm almost speechless!



I know, quite embarassingmajorly so.
This is when I started to collect orchids. reading that charcoal is good, I put the seedling in pure charcoal.


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## NYEric (May 22, 2009)

OK, but did you read that orchids don't like fertilizer also!?


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## Hien (May 22, 2009)

NYEric said:


> OK, but did you read that orchids don't like fertilizer also!?



It is very weird, I have the same story about Super-Thrive.
For other peoples it seems to do amazing things (at least , that is what they say) But , a few times that I put it in the semi-hydroponic, the next day I would notice all of my orchids got yellow leaves (if I remember correctly, they all started with the lowest & oldest leaves first, and may even lose all the leaves had I not dump the water out ) wonder if it was because the water was not pure and the stuff made the orchids used more of the unpure chemical in the water.


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## NYEric (May 22, 2009)

True, maybe you burned the plants! I'm not the biggest fan of S/H because if the holes are high and you dont flush water out through them then the plants stew in a potentially toxic soup!


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## Rick (May 23, 2009)

Ray said:


> Hoo boy. I hate the "things seem" reason, even if I've used it a thousand times myself!
> 
> .



Makes it more like religion than science that wayoke:oke:

"I have noted that in old medium, charcoal seems to have a particular "feature" of building up minerals faster than other components. maybe it's just because it's black that it looks that way"

Could be, and it may actually be all crusted over on the surface from plain old evaporation.

On thing I forgot to mention that carbon is also good for is chlorine reduction.

It's a "catalytic" reaction rather than absorption as for organics and metals. Subsequently, carbon has almost infinite capacity to take chlorine (not chloride) out of tap water.


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## Rick (May 23, 2009)

NYEric said:


> True, maybe you burned the plants! I'm not the biggest fan of S/H because if the holes are high and you dont flush water out through them then the plants stew in a potentially toxic soup!



At the Memphis show I saw an award (AM) winning Catt. schilleriana that was grown SH under lights. I saw the old growths from when it was in a standard bark mix, and it was huge and green in comparison. A truly awesome plant.

I'm still kind of picky about what stuff I put in SH, and it hasn't been a panacea for some of my problem children. But there are definitely growers that do great with it.

Candace uses the system extensively.


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## paphioboy (May 23, 2009)

> How big is the charcoal that you use? you plant paphs in soil?
> I think maybe there were a few reasons, looking back.
> -they were very small particles (less then 1/4 inch) so it may hold too much water, no air.
> -I did not fertilize the plant, so there was no food, whatever minerals from the water were probably all zapped by the charcoal.
> Reply With Quote



Hien, for phals, charcoal pieces of size 1-2 cm will do. Clay or plastic pots does not matter. But we can accomplish that in the tropics due to the high humidity here. Orchids can and will grow well without fertiliser for quite a long time, although it is not advisable to purposely deprive them of food. For example, while I'm away in Australia, none of my orchids get fert at all, as I'm afraid they might get over fed and suffer root rot instead. 

Oh, yes, I plant paphs in soil. Ready to use garden soil + fern root + charcoal + limestone + leca/broken pot shards etc..


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## Ray (May 24, 2009)

Folks who claim s/h is a panacea were either really bad at water and air management in the past, or haven't experimented with enough genera!

There is a lot more to "orchid culture" that medium/pot/watering mode.


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## Rick (May 24, 2009)

Ray said:


> Folks who claim s/h is a panacea were either really bad at water and air management in the past, or haven't experimented with enough genera!
> 
> There is a lot more to "orchid culture" that medium/pot/watering mode.




I agree totally:clap::clap::clap:


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## Roth (May 24, 2009)

Busy thoses days, but anyway:



Hien said:


> It is very weird, I have the same story about Super-Thrive.
> For other peoples it seems to do amazing things (at least , that is what they say) But , a few times that I put it in the semi-hydroponic, the next day I would notice all of my orchids got yellow leaves (if I remember correctly, they all started with the lowest & oldest leaves first, and may even lose all the leaves had I not dump the water out ) wonder if it was because the water was not pure and the stuff made the orchids used more of the unpure chemical in the water.



No, I got the same problems with some chemicals combinations, and the explanation is simple:

- Let's say you have a plant borderline deficient in iron. You will use a fertilizer because it looks a bit chlorotic, but that fertilizer is not able to supply enough iron. You end up with a greater chlorosis, the nitrogen will push the plant to "grow", but there is still not enough iron, and because of the extra growth, the total iron content of the new leaves dropped even more.

For Superthrive, I use a proprietary mixture of quite a lot of things, amino-acids, some others compounds. If the plants do not have enough food, thoses boosters will make the matter worse. If previously you had a nitrogen deficiency, using Superthrive or any other growth-booster will make matters worse, push the plant to grow, but no food to sustain that...



Hien said:


> How big is the charcoal that you use? you plant paphs in soil?
> I think maybe there were a few reasons, looking back.
> -they were very small particles (less then 1/4 inch) so it may hold too much water, no air.
> -I did not fertilize the plant, so there was no food, whatever minerals from the water were probably all zapped by the charcoal.



The good question is which wood has been used to make the charcoal exactly... Some are extremely acidic, some have weird mineral contents... 

For me, I stopped using the charcoal in Vietnam because I found out that the plants did not like it too much, at least not worth the trouble. And second reason, the Vietnameses do not supply anything standardized when it comes to mixes, except some imported items. It is impossible to have 1/4 inch charcoal or 2 inches charcoal, it will be a mixture of all the sizes.

Au Yong -who just passed away- was growing great plants in Kuching of all the Paphiopedilum including sanderianum and stonei in pure charcoal, watered with the local river- passing through a lot of limestone hills  

Another amazing thing is that he had some paph micranthum and others given by one of his customers from Hong Kong, and they would grow very well even with 38C+ temperatures, not bloom but grow. He watered every day, sometimes twice a day. His display - for scam - area was growing so great in pure charcoal.

As a side note, I went to his nursery three times, and it was impossible to receive by cargo the plants that I selected... I discussed with some others professionnals, and it was apparently typical from this nursery. Go there, visit the beautifully grown paphs, make the CITES/export permits, choose one by one and pay all the plants. Then there was always a problem, like a delay in the cargo shipping, the customs officier not here, etc... and at that time they would swap the plants.

I remember I went there in middle of july, to buy some hundreds paphs, with all the permits ready on both sides. I choosed those for 3 days, stayed until the cargo could leave. one, two, three days, 1 week, 2 weeks in the Holiday Inn close to the river, next day, two days, customs officer sick, then phyto inspector in holidays in Bako, etc... Then at the early days of august, I had to leave. 

Got the plants by cargo 3 days after my arrival in France, and received only crap, small plants, some maybe very freshly jungle collected. Only 1/5th of the shipment were the large beautiful plants I selected, the remaining only crappy plants of 15-25 cm with 3-4 leaves... It was typical from this nursery unfortunately, never allow the customers to care about the shipment themselves and swap some/most the plants. But he was nevertheless a great grower.

Back to the charcoal, I did not find anything beneficial in its addition on my side...


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## Hien (May 25, 2009)

Thank you for the explanation, Sanderianum.
It made sense of what happened.
For a long time I could not figure out that strange reaction from my plants. 
I realize now that great growers can almost communicate with their plants (actually so in tune with the plants that they are able to tell what the plants need, and fullfill those need)
and average growers like me always chasing after the next miracle formula, which does not apply to the particular needs of our plants, sometimes actually make it worse.


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## Rick (May 25, 2009)

Hien said:


> Thank you for the explanation, Sanderianum.
> It made sense of what happened.
> For a long time I could not figure out that strange reaction from my plants.
> I realize now that great growers can almost communicate with their plants (actually so in tune with the plants that they are able to tell what the plants need, and fullfill those need)
> and average growers like me always chasing after the next miracle formula, which does not apply to the particular needs of our plants, sometimes actually make it worse.




Quote:
Originally Posted by Ray View Post
Hoo boy. I hate the "things seem" reason, even if I've used it a thousand times myself!

.
Makes it more like religion than science that way


I really think that people who are good at taking care of any living thing (people, plants, and animals) are great at communicating with their subjects. I worked in the zoo biz for many years, and sometimes I noticed some of the best zoo keepers had some of the worst human-human communicating skills.

I find plant people to be very congenial


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## biothanasis (May 25, 2009)

Rick said:


> I noticed some of the best zoo keepers had some of the worst human-human communicating skills.



That is true and logical!!! It depends on what types of human they communicated with! Also a person can be perfect at his/her work, but this does not make him/her a person with normal behaviour!!!  Then it comes with values, morals etc!! Human behaviour was, is and will always be very complicated!!


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## Renegayde (Jun 13, 2009)

while recently searching the web for components to make my own potting medium I came across this http://www.paghat.com/charcoal.html
makes me wonder if I should even bother adding charcoal to the mix


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## Rick (Jun 13, 2009)

Renegayde said:


> while recently searching the web for components to make my own potting medium I came across this http://www.paghat.com/charcoal.html
> makes me wonder if I should even bother adding charcoal to the mix




I don't know. The line about "filtering carbon only lasting 15 minutes in aquaria" makes me wonder about the legitamacy of the entire article. If there is a material in an aquarium (that is absorbed by carbon) at concentrations that would saturate it in 15 minutes, then that filter is either completely undersized for the aquarium or the fish are already dead from the compound in question.

As I pointed out earlier, activated carbon (definitely better than horticultural carbon) has almost infinite capacity to dechlorinate tap water (because this particular function is catalytic on the surface of the carbon rather than absorbed to it). At work we process multiple thousands of liters of tap water through a four foot tall, one foot diameter tank of carbon with no breakthroughs of chlorine, copper, and zinc, and TOC (total organic carbon)stays less than 5 ppm.

This is just calgon activated carbon of no particular special grade. 

I quess if I get ambitious I can try a pour through test (at work sometime) of some of my hort charcoal with some source of COD or tap water for chlorine, and see if I get any removal.

For those who use tap water for irrigation, several of the growers in the Nashville, TN area added carbon (and/or those new funky silver) filters to remove chlorine from the tap water they use for irrigation, and saw significant improvements in short term culture.


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## PaphMadMan (Jun 13, 2009)

The terra preta soils of the Amazon Basin are patches of dark soil of sustained fertility. They appear to be essentially man-made by addition of charcoal, crushed pottery and organic matter to the naturally infertile rain forest soils. Wouldn't this seem to suggest that at least for terrestrial orchid mixes that charcoal might be advantageous, whatever the specific contributions of the charcoal may be?


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## Rick (Jun 14, 2009)

PaphMadMan said:


> The terra preta soils of the Amazon Basin are patches of dark soil of sustained fertility. They appear to be essentially man-made by addition of charcoal, crushed pottery and organic matter to the naturally infertile rain forest soils. Wouldn't this seem to suggest that at least for terrestrial orchid mixes that charcoal might be advantageous, whatever the specific contributions of the charcoal may be?


 
I think that could be a good point Madman. Even for as much as GAC has been studied, and parameters understood for waste water technology, the science keeps finding out new stuff all the time, and there are other more complex interactions that are not understood.

There are many natural plant / spirit medicines used by Shamans in the same areas as many of our favorite orchids come from, and they have been keeping their people healthy with them for centuries before western science isolated the medicinal properties from the plants to turn them into pharmaceutical drugs.


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## gonewild (Jun 14, 2009)

If you have natural charcoal use it. 

In Peru I grew over 300 species in a mix of CHC and charcoal. The CHC came from coconuts that fell from our trees and the carbon came from the local market where people buy it to cook with. Every species flourished in the mix. Charcoal is a great additive to orchid media as long as it is not contaminated.

All of my paphs and phrags are now in a mix that contains about 10% charcoal and they grow great under lights. Next repotting amd the mix will likely be 30% charcoal.


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## Renegayde (Jun 14, 2009)

the mix I want to make calls for 25% charcoal


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## gonewild (Jun 14, 2009)

Renegayde said:


> the mix I want to make calls for 25% charcoal



Exact % is not important. 25%, 30% or 50% won't make much difference. Charcoal should not rot like other organics so higher percentages will tend to extend the life of the media.


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## Jim Toomey (Jun 14, 2009)

gonewild,
Could there be too much of a good thing?
I know you said the exact amount won't make much difference, but
what would the maximum amount be?
Thanks


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## Rick (Jun 14, 2009)

Jim Toomey said:


> gonewild,
> Could there be too much of a good thing?
> I know you said the exact amount won't make much difference, but
> what would the maximum amount be?
> Thanks



I think Sanderianum told us about a grower in Indonesia that grew sanderianums
in 100% charcoal. But I don't think any one else has replicated that technique successfully. There really are allot of variables to consider besides individual components of a potting mix.

My mixes have 10-20% for reference.


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## paphioboy (Jun 15, 2009)

Rick, its Au Yong's nursery in Sarawak (Malaysia), not Indonesia.  My paph sanderianum seedling is not doing well in its current medium. I think I will change it to 100% charcoal and see what happens before it KOs...


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