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Charcoal and Orchids. Myth, Magic I know I would never grow an Orchid without it after 40 years!

I have used charcoal in my orchid mix for 41 years.  
It is one ingrediant I wont leave out of my mix. How it all started for me was when I was a 16 year old apprentice I was asked to seive out the larger peices of a commecial potting mix as the boss wanted a seed raising mix and the one we had purchased had too many big bits in it.
What remained in the seive was roughly this  5 parts graded pine bark, one part charcoal and one part scoria  (Red volcanic bubbly rock)
Does that sound familiar, Its the same mix ive used for 40 years straight. Never varied it.
This is how we make up the blend.
But the charcoal was always difficult to obtain.
These days I buy 18 pallets at a time when I can obtain the right grades.
All i ever knew is that if the charcoal wasnt in the mix the results were poorer in every way.
Remember if I use it we sell it
Here is someone elses opinion.

Very few people know the benefits of using charcoal and even fewer have a positive word to say.

Charcoal is by far one of the most important components in a Potting mix. Good quality, hardwood charcoal is rare and many nurseries have none for sale. It is “good business” to recommend something “that is better”. Bad quality charcoal, made from soft pinewood, timber off cuts or remains from a fireplace, are not a good alternative and should not be tried.

Charcoal is the product of slow burning natural wood in the absence of oxygen to prevent combustion. The burning occurs at temperatures of 400°C – 500°C (750°F – 930°F). Coal is not Charcoal and cannot be used in its place.

The motivation for using charcoal in agriculture for soil correction follows the discovery in the Amazon of "Terra Preta" or Dark Earth (Black Soil), the most fertile soil known to man. These “Black Soils" contain charcoal many times over that of the surrounding areas, a fact that explains the high quality of vegetation and soil fertility in the area.

Charcoal is added in to potting mixes for two main reasons:

a. to keep the "mix" sweet.

b. to filter impurities. 

Laboratory tests show that charcoal possesses a remarkable ability to:

1. Keep nutrients in the soil and that way increase soil fertility.

2. Prevent decay and can endure in soil for thousands of years.

3. It is inert.

4. Allow the flow of air through the potting mix.

5. Retain moisture and help in good drainage.

6. Retains (adsorbs) excess nutrients (fertilizer), and release them later when needed.

7. Helps to increase the soil pH.

Charcoal has a very long “shelf life” in soil. That explains the high productivity of charcoal enriched soils. Charcoal, being absorbent, accumulates minerals salts (heavy metals) that can cause damage to the root system of the plant, causing the burning of the root tips.

Some "experts" recommend to growers using charcoal, to re-pot the plants on a regular basis in order to avoid root damage and plant poisoning; however, orchid growers use rain water or tab water (water suitable for human consumption) for watering, both types of water are free of any salts. Fertilizers used contain only traces, if any, of heavy metals or salts. Charcoal does not harm plants, on the contrary.

Charcoal has the tendency to bind toxins from the metabolism (breakdown) of the organic components of the potting mix, for example pine bark, resulting in doubling the life of some potting mixes. For example: Sphagnum moss has normally a life span of 6 months; however, with 10% charcoal added, the life span increases to over one year. Pine bark has a life span of about 12 months and again with charcoal added, the life span can increase to two years.

 Getting bored? I get bored fast when reading so watch this 

Another opinion      Discussion Orchworks

Hardwood charcoal has some qualities that work for the above. It is slow to decompose, helps drainage, provides some air circulation. 
Most potting materials for orchids do not provide any nutrients. We add the nutrients in the water via the fertilizers we use and that’s how they are made available to the plants. 
I am sure charcoal does bind some salts but hardwood charcoal does it less readily than activated charcoal. It also may also absorb some of the toxins from the breakdown of the organic material in the potting mix and those in the water. That is a good thing. I had seen one article, from a taxonomist, that some toxins are released from an orchids roots, which will be absorbed by the charcoal. 
I don't think it needs to be used but there are many pros for it to be in a potting mix.


And worth a good read

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  • Roger Small on

    We make the charcoal to order for Wayne. In order to produce to Waynes high standards we take our chemical free Australian hardwood from our private native forestry operation. We then turn it into charcoal at 950’c. This high temperature creates a product equivalent to activated carbon and results in a charcoal which is basically free of volatiles, holds more than 100% of its own weight in water and will not break down over 100’s of years . We then grade it in sizes 5-12mm and 12-25mm.
    I can personally vouch for the quality of the charcoal and Waynes professionalism
    Roger Small
    Spinifex Country Products

  • Darren Hynes on

    Have never used charcoal. I use perlite and vermiculite together or bark and perlite. I’ve seen perfect specimens in either and some just in plain old bark itself.

  • Wayne Turville on

    It seem there are many ingrediants used world wide .
    Basicaly what is suited for that country or even region within a country.
    I dont know the medias you have mentioned so cant comment or advise so sorry.
    All i know is I would never ever use an orchid growing media without charcoal in it.
    Asian countries use charcoaled coconut shell (Like black glass) with great efferct.

  • Bogdan on

    The charcoal seems to have so many advantages! Until now I grew using either s/h with Hydroton or classic bark mix with pumice. This article inspired me to think about a 1:1 charcoal and Seramis (sort of a pumice-Hydroton mix clay) for a pseudoinorganic medium for cattleyas. What is your opinion regarding this? Thank you!

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