Don't Throw Your Used Orchid Bark Away

[Phred]

I make my own orchid mix that contains bark, pumice, perlite, expanded shale etc. I have never used charcoal because it's too expensive and I have a lot of plants.
My 'Great" idea... Lol
I take all of my used orchid mix and turn it into charcoal... here's how

Heres my barrel of used mix.

I fill a empty paint can I got from the paint store. Put a nail hole in the lid and place securely on the can the place it over a fire.
View attachment 20250104_134922.mp4

Once the can and tents get hot steam the fire will come out of the nail hole. Once the flame stops coming out of the nail hole take the can out and let it cool off completely.

What's left inside is homemade charcoal for you next batch of orchid mix.

 

[Linus_Cello]

How do you clean the paint out of the can? How do you separate pumice, etc from charcoal?

 

[Phred]

How do you clean the paint out of the can? How do you separate pumice, etc from charcoal?

I don't... the plant parts as well as any moss turn into char also. Those things can break up pretty small so from now on I'm separating it out ahead of time. As for the pumice and other stuff I use, it just goes through the process with the bark. The high heat burns off any fertilizer or chemicals and I just add it all back into my new batch of orchid mix. I'm always happy with more inorganic material but it's not that much more in the end.

 

[Ray]

The high heat burns off any fertilizer or chemicals and I just add it all back into my new batch of orchid mix.

I doubt you're "burning off" nearly as much as you think. Most fertilizer ingredients are inorganic mineral salts, so may not be burned off at all.

Calcium nitrate, for example, melts at around 1041°F, and I doubt you're reaching that, so any residues just sit there. I imagine some of them become oxides, if you let in enough air.

 

[Ozpaph]

horticultural charcoal is made from hardwood. Burnt 'bark' will disintigrate quickly.
Im also concerned about the accumulated 'salts' and wouldnt re-use the mix for orchids. Probbaly fine for the garden/pot plants

 

[Phred]

I doubt you're "burning off" nearly as much as you think. Most fertilizer ingredients are inorganic mineral salts, so may not be burned off at all.

Calcium nitrate, for example, melts at around 1041°F, and I doubt you're reaching that, so any residues just sit there. I imagine some of them become oxides, if you let in enough air.

Many woods burn at temperatures over 1000⁰ F.
Oak - up to 1652⁰ F
Spruce - up to 1148⁰ F
Just to list a couple that burn hot enough to clean it up.

horticultural charcoal is made from hardwood. Burnt 'bark' will disintigrate quickly.
Im also concerned about the accumulated 'salts' and wouldnt re-use the mix for orchids. Probbaly fine for the garden/pot plants

Ozpaph... which do you think disintegrates faster - bark or the same bark carbonized. That would be the new bark.
They way you recharge charcoal is to expose it to high heat which this process does.

Check out:
climate.mit.edu

 

[Tom-DE]

Actually charcoal isn't that expensive, A 50-pound bag of charcoal costs less than a good Paph and it will last for a long while...
I put my old bark mix in the garden beds....

 

[niche]

Its a great idea and if it works for you keep doing it. I think this is a great idea. The cautions mentioned above make sense, but overall it is a really good idea.