Terra Preta.

[Farmer Dave]

I have been trying out the basic concept of Terra Petra which is adding charcoal to my soil. I end up having a lot of brush and fruit tree pruning to burn on our land so I just use the charcoal build up with the ashes. I am doing one section of my garden as I have a large garden so I can ascertain if it is working. Will I be adding the same product as if I used a no oxygen burn barrel?

I have very well drained soil that is a little gravely which is nice to work but leaches nutrients very quickly. As I under stand it the charcoal will help to hold and bind nutrients to the soil. I must say I am a bit to new to this experiment (2 years) to really know but I think it is working to some degree.

[The Helpful Gardener]

A better product actually, FD Same excellent char structure, less GHGs. Good for soil, good for the atmosphere...

Here's the thing FD you are adding a big cation sink with charcoal. If you do not have a serious biological culture in your soil, one that populates the char and starts weak acid responses to help etch the nutrient back ot of those strong covalent carbon bonds, you can lock up more nutrient than you release to your plants. I think you know where that goes.

Make sure you are using this in conjunction with good active compost, and plenty of it, at the start. Once the char gets populated it will start to self-sustain as you will get the poop looping from the protozoan predation of bacteria, as well as the weak acid releases. But if somebody is just dumping on the ammonia salt, it will likely just sit in their charcoal sponge and wait for biological releases that just aren't coming... Nature works best with Nature, and poorly with man made chems...

HG

[Joyfirst]

Do you guys grind up the char somehow before adding to the soil?

[The Helpful Gardener]

Most do; it increases the surface area and that means it hold more nutrition...

[rainbowgardener]

Do you guys grind up the char somehow before adding to the soil?

Without a grinder, the low tech way would be put it in a bag and pound it with a hammer!

[The Helpful Gardener]

Or do like T$B and drive on it. I worry that powders it too much, but I have been assured it will not.

I notice we keep talking about the charcoal component, but the true terra preta also included a fired clay introduction. My assumption has been this was a water retention addition, but there would also be some CEC increase. Anybody trying this part of the puzzle?

HG

[Toil]

I think it should be mentioned that adding char to your soil does not make terra preta. The terra preta recipe is a long-lost secret unknown even to the indigenous tribes of the amazon. Either European pathogens wiped all that out, or the knowledge was no longer necessary long before that.

That said, heed HG's words.

I am playing around with it myself, by adding it to my worm bins. Another technique I've heard mentioned is to soak it in fertilizer. Something like fish hydrolysate.