While someone may suggest saving the leftover charcoal after a barbecue gathering for gardening use, another may believe that the use of filtering charcoal can yield better performance in purifying the potting soil. None of these is either feasible or true, but only an urban myth of horticultural charcoal. Not all charcoal are created equal. And horticultural charcoal cannot substitute by either barbecue charcoal or filtering charcoal.
Horticultural Charcoal & Barbecue Charcoal
There are binders added in barbecue charcoal, and they are reported as sufficiently toxic to plants, and in consequence, make barbecue charcoal and its ashes not recommended for composts or garden soil enrichment.
Horticultural Charcoal & Filtering Charcoal
Filtering charcoal is not the same thing as horticultural charcoal. Most that are sold for aquariums today is not a wood charcoal at all, but are made by a completely different process from bituminous coal, peat, lignite, hardwood, or animal bone, followed by further processing & chemical washes. It retains a great deal more water than horticultural charcoal, yet less oxygen. Unlike filtering carbon, horticultural charcoal is untreated and unprocessed, hence, a more natural product.
Because filtering charcoal is an activated carbon, it has lots of air pocket, hence can absorb odors. Horticultural charcoal cannot absorb odors, for it merely is a cheap grade of natural charcoal that has not been activated. Check out Horticultural Charcoal Myth #2 Absorb Odors for more details on this topic.
Back to main page – Holticultural Charcoal for Gardening
Mingxin Guo is an assistant professor in the Agriculture and Natural Resources Department at Delaware State University. When asked if one can use the type of charcoal sold in supermarkets for barbecue, his reply: “Theoretically, you can buy some charcoal directly from a supermarket and grind it into small grains and apply it to the soil.”
Now, when you show all of us the results of YOUR scholarly research, and that research is published and stacks up to Dr. Guo’s, perhaps you will have even a modicum of credibility. In the meantime, you do a disservice to your readers in publishing such ignorance as you have on this page.
Thanks for letting me and my readers know about this Jackie. I really have done no “scholarly research” on this topic but just wrote whatever I learned and knew. Apparently, what I wrote is not totally accurate. And thanks to people like you who help correcting others. This is how we learn, thru discussions, experiences, trials and errors… Thanx god that I have enabled this comment session in the first place 🙂
What can Horticultural Charcoal do to plants?I am doing a science project about a biosphere and I need to know.
Did you make this website??????????
Hi Calvin,
What do you mean?
Charcoal is exceptional in 2 ways:
1) Like other forms of organic matter, it is excellent at raising the nutrient holding capacity of soil or potting mix.
2) It lasts in the soil much longer than other forms of organic matter. Composts often completely break down in a course of years or decades. Charcoals can last centuries or millenia, depending on the chemical structure and environmental conditions.
You are right that charcoal itself does not have much in the way of nutrients. But it can have very beneficial effects on the soil – it reduces leaching of nutrients out of the soil and it increases beneficial microbes in the soil.
I understand that filtering charcoal is not the same thing as horticultural charcoal, but can it provide some of the same benefits? Will it do any harm if I use it? The reason I am asking is because my boyfriend cleans fish tanks for a living and so has a lot of used activated carbon from fish tank filters that would otherwise go in the trash. We mix our own potting soil, mostly for cacti, so if we can use this as a free soil amendment that would be awesome.