Charcoal as growth medium - what kind?

[Silje]

Hi guys.

I see that many use charcoal in growth medium mixes and I'm considering trying it, but charcoal harvested in the wild, not purchased.

The thing is I live on a farm with regular bush fires and I can harvest naturally burnt acacia charcoal pretty easily and it's free!

It definitely does not contain chemicals in the line of herbicides or pesticides of any kind, but I'm not sure if charcoal sold for horticulture purposes are just...plain charcoal or if something has been done to it in addition to the normal processing/burning.

I'm not always happy with using fir bark as growth medium. I think the chip sizes I can get hold of are either too big or too small, and that the nurseries here lack medium sized bark, and I've been thinking that perhaps own harvested charcoal could be an alternative.

What are the pros and cons of charcoal? And what do you guys prefer to mix it with?

[Vanda lover]

I'm sure that you can use your brush fire charcoal. I use the stuff from fire pits with no problem.
I like a mixture using coconut chips, perlite, charcoal and bits of moss if I have them. I'm not fond of bark because I like to be able to feel the medium to tell if it is damp. With bark it's hard to tell if it is dry underneath. I do sometimes add bark to mt mix if I have it. For my vandas, charcoal and sphag work well.

[euplusia]

I don't use charcoal, but I know that people who do buy the one that is used in water filters for an aquarium. It's cheap and chemically okay.
Another point of importance is the acidity of the wood and it's coal.
Using coal you have to water a lot. But give it a try.

[biofuel]

I don't think that is good idea. Charocal could catch ions and it may influence for orchid growth

[Vanda lover]

Orchids love charcoal. Many people grow in just charcoal

[AnonYMouse]

Charcoal by itself is pretty inert. It doesn't do much but occupy space. It doesn't decay so it doesn't feed organisms. It does function as an absorbent and keeps media "fresh". It isn't water retentive so keep that in mind. Those are the reasons why growers use it in mixes.

To maintain freshness, it does have to be changed (just like filters). How frequent is dependent on what and how much it is exposed to.

Any properly heated woods should be fine. Make sure resinous woods are heated completely through (you should not see any woody cells or glossy blobs).

I have heard of someone using charcoal exclusively but I don't know how successfully.

---------- Post added at 03:23 PM ---------- Previous post was at 03:15 PM ----------

Originally Posted by Vanda lover

Orchids love charcoal.

Not ment to offend but I found the statement funny because I think of charcoal as being indifferent. Yeah, I have a very strange sense of humor. And no, i do not normally anthropomorphize chunks of carbon.