Author Topic: charcoal in the soil mix  (Read 4322 times)

bonsaiTom

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charcoal in the soil mix
« on: October 03, 2011, 05:41 AM »
At our last club auction I acquired a nice little tiger bark ficus in a pot made by one of our potter members. The soil had an abundant amount of charcoal in the mix. Well the little tree is really flourishing. I'm not much of a ficus guy and not really into tropicals, though I have a few. Anyway the soil intrigued me as much as the plant and pot - so I bought it. Compared to my other trees this mix is so nice and loose, light, airy. Never gets packed down at all. Water really 'filters' through.

Now I'm wondering about the charcoal. Went out and got some - labeled horticultural charcoal - and want to add it to my standard mix for use when re-potting next spring. But first I want to do a little homework. What can you folks tell me, from your experience, about this stuff. Is it as good as it seems for my tiger bark? Long lasting? Best only for trop's or good only for certain trees? Any warnings to offer? All advice is appreciated.
 

MatsuBonsai

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Re: charcoal in the soil mix
« Reply #1 on: October 03, 2011, 08:22 AM »
I wonder if you might list the rest of the ingredients and their estimated percentage. Also, the same as your regular soil.

I've been using about 5% charcoal for years, but I suspect what you're seeing has more to do with the loose, light, and airy.
 

AlexV

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Re: charcoal in the soil mix
« Reply #2 on: October 03, 2011, 12:20 PM »
I have added charcoal to my soil mixes (Boon's mix) and didn't notice a huge difference.  Activated charcoal soaks up large molecules, hence why they use it in a lot of filters.  I know a lot of people who use it, but mostly in small quantities like John mentioned.

Alex
 

Treebeard55

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Re: charcoal in the soil mix
« Reply #3 on: October 03, 2011, 03:53 PM »
... I suspect what you're seeing has more to do with the loose, light, and airy.

I suspect John's right, especially since your tree is a Ficus. Rainforest topsoils are typically quite loose and free-draining, so anything that imitates that structure would be a plus with most tropicals.

I've never added charcoal to a mix, tho I may try it next time I repot my ponderosas. I understand it's used mainly to raise the pH a tad, keep the mix from being too acidic.
 

Elliott

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Re: charcoal in the soil mix
« Reply #4 on: October 13, 2011, 02:26 PM »
this last 2 years I have been sprinkling a lil charcoal on top of the drainage layer (the first layer soil that goes into a pot that is usualy made up of larger size akadama or scoria or whatever to facilitate drainage-as done in Japan) with a small amount of mycchorizae (or however you spell it)powder, then my regular soil mix that Travis at California bonsai studio mixes up for me.
 I know that charcoal absorbs toxins, which at first sounds like a good thing, but maybe those toxins should just get washed out of the pot instead? Maybe the charcoal absorbs nutrients also? I will try for a few years and see. If I get results, I will keep it up. I have noticed that charcoal near the drainage holes will breakdown and gum it up a little and thereby inpede drainage, that's why I sprinkle it above the drainage layer and not into the general mix.
 I think it probably does not make a big differance.
 

John Kirby

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Re: charcoal in the soil mix
« Reply #5 on: October 13, 2011, 04:57 PM »
Like John, I too add to my otherwise in organic mix (about a cup per 5 gallons), the scientific literature s pretty silent on this, I do know that charcoal is a good way to keep carbon sequestered for a millennium or two....
 

bonsaiTom

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Re: charcoal in the soil mix
« Reply #6 on: October 14, 2011, 05:19 AM »
Thanks guys. I see no harmful effects noted. The ficus continues to seem very happy. I am trying now with a couple 'bougies'. John asked about the other components in the mix. Can't tell you much about the mix for the ficus in question except that the charcoal portion is high - perhaps as much as 30% - with pine bark chips and crushed granite. This is "as purchased".