[TerryPradha]

Talking about mixing charcoal in pots made me think about getting soil ready for next winter. I bring in a select set of plants each year and having a char soil mix sounds like a good idea.

Would campfire chunks be used as the drainage pieces, instead of stones? Are the mixes mostly charcoal with other stuff mixed in? or Mostly other stuff with some char mixed in?

[Michaelangelica]

Originally Posted by nutronjon

Excuse me, about the charcol Can I buy a bag of the charcol used for barbecuing and break it up with a hammer and throw it into my soil mix,

Yes.
but
as freezar said, be careful you don't buy what is sold here as "BBQ fuel" which is full of binders and kerosene? to help it burn.

[Michaelangelica]

[quote=TerryPradha;216893]Talking about mixing charcoal in pots made me think about getting soil ready for next winter. I bring in a select set of plants each year and having a char soil mix sounds like a good idea.

Would campfire chunks be used as the drainage pieces, instead of stones?

Sounds OK Broken terracotta pots would be cheaper.

Are the mixes mostly charcoal with other stuff mixed in? or Mostly other stuff with some char mixed in?

depends abit on the plant carnations and lime loving plants will take alot Camelias and Gardeneias-acid lovers- etc will take less.
for starters I would go with

Mostly other stuff with some char mixed in?

When the "other stuff" is a good potting mix. Experiment and see.

[Essay]

Originally Posted by TerryPradha

Are the mixes mostly charcoal with other stuff mixed in? or Mostly other stuff with some char mixed in?

...from "1491" by Charles Mann

terra preta contains up to sixty-four times more [charcoal] than surrounding red earth.

...but 64 times nothing is still a pretty small amount.

I know there's at least one reference on that "Contents for T.P...." thread.
i.e. post#62:
The percentage of bio-char in Terra Preta varies from 20-40% and comes in two types: black charcoal and brown. The two types are apparently the result of producing the charcoal at relatively low temps. The brown charcoal is much higher in plant resins and these are thought to be used by the microorganism community in binding nutrients.

Don't think of T.P. as a special alternative substrate or growing medium; just think rich, organic dirt, with enough char added to improve color, workability, humectancy; and the magic stuff will take care of itself....

[nutronjon]

Originally Posted by Michaelangelica

Yes.
but
as freezar said, be careful you don't buy what is sold here as "BBQ fuel" which is full of binders and kerosene? to help it burn.

Thanks that will save me a bundle. I already figured I want to avoid any additives in the charcol. And I appreciate the explanation of how much to use. If I understand correctly, that is a lot of charcol. I figure I will buy one small bag of pure charcol if I can find it. Smash it up as best as I can, and add it to the soil I hope to buy for my 10X20 plot. Is this about right?

We have volcanic ash about 12 inches down, and I wish I had the strength to rototile that up. Hopefully the person before me rototiled the plot well, but it is too much clay! I need sand really badly, but have to cut cost somewhere. A load of top soil is pushing my budget. Maybe I should go for sand instead of rich top soil, but the sand would need to be rototiled in and I just don't have the strength for that?

[UncleAl]

Terra preta soil is best as activated charcoal. About 10 wt-% granular charcoal replacing sand retains drainage, makes fertilizer more effective, and really juices up pots and the garden. Powdered charcoal will *not* improve drainage. Little jars of activated charcoal are grossly overpriced. These folk are a little looney in philosophy but rock solid as honest bulk vendors. (Link titles do not commit you to purchase)

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[freeztar]

Originally Posted by UncleAl

Terra preta soil is best as activated charcoal.

Where did you read that Al?
From all the info I've read here, low temperature charcoal (450C) is best for soil.

[Essay]

Originally Posted by freeztar

Where did you read that Al?
From all the info I've read here, low temperature charcoal (450C) is best for soil.

Good point, from what I understand about TP.

I wonder if those guys who clean office aquariums just toss their used charcoal. It would be "de-activated."
More than that, it would be re-resinated and pre-primed with nutrients and beasties (that'd then get eaten by the soil microbes).

[Ahmabeliever]

That's some misinformation there allright. Ancients weren't making activated charcoal and so nor am I.

Pyrolised. I really want some low temp stuff to see how fast the bacteria in my aqua beds can chew up the remaining resins....

Also want to test granulated resins on worms and soldier flies. Might be that they directly eat what we consider to be pollution. (well, it is if burnt).

I know bacteria consume this waste, but how fast?

[Michaelangelica]

I hate to agree. It goes against the grain.; but Uncle Al could be part right.
(Where is my diamond Al!!)

Activated charcoal certainly has more Condos (Eric's word) for 'wee beasties', adsorbs more everything -fertiliser, water, pesticide et al
But
Non-activated charcoal (low temp 350-400C) contains more bio oils which feed "wee beasties". Besides it is too expensive to consider activated-charcoal unless you can get waste AC for free.
BEST Energies pyrolysis 'machine' can "part-activate' charcoal if you ask them to" make it so"!.