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How to make Terra Preta soil (Amazonian Dark Earth, Black Earth)

Tony Callaghan 03/03/2022

How to make Terra Preta soil (Amazonian Dark Earth, Black Earth)

How to make Terra Preta soil

You probably already know Terra Preta is a super fertile, long-lasting soil found in certain parts of the Amazon rain forest. If you want to read about Terra Preta jump to this blog. These patches of soil were made by ancestral tribes. The recipe is long lost, but many people are seeking to re-discover it. We believe we have come as close as anyone else in the world to cracking it. We are happy to share some of the knowledge to get you on the right track.

Assuming most readers have clayey soil, add 20% biochar Super Compost to your soil (ie 1 part SF60: 4 parts soil. If you have sandy soil add more SF60 (1:3), if you already have good loam soil add 10% SF60.

What is Biochar Super Compost (SF60)?

If you are new to biochar and want to know more, hop over to our extensive blog. We cannot overstress this: adding raw biochar to your soil will not create Terra Preta - it will take many years via this route.

Where do I get SF60 - Biochar Super compost?

If you just want a fast and easy way to improve your soil, hop over to our shop and buy SF60. However, if you already have a compost heap, you might be more interested in making your own version at home.

How do I make it myself?

To make a biochar super compost, add the SoilFixer Colloidal Humification Agent to your composting process.

It will work in any compost bin or heap.  However, we do find it works better in a hot composting system with no turning (for example the HOTBIN. (In fact, the recipe came from observations and experiments from years of using the HOTBIN and seeking how to make a better compost!).

The exact formulation is a patent-pending trade formulation. You will note from the product description it is 80% carefully selected biochar and 20% 'micronised oxides'.  We have various ideas on how and why it works. What we do know is it the product helps create more colloidal humus and it is this item that appears to be the 'magic' ingredient within Terra Preta.  (Others may believe that biochar creates Terra Preta. We are 100% convinced that simply adding biochar to the soil does not work (at least at first). That adding biochar to compost and then the mix to soil gets you closer, but it is not even close to the impact you get from adding the humification agent to compost and the combined effect of hot composting and no turn.  (Our European patent for the method/recipe has been pending for 5 years - it now appears we might be just a few months away from great - yeah!!)

Why is Terra Preta worth making?

In our trials (which do need large-scale validation) the product rapidly increases soil fertility in the first year by at least 20% and up to 100% for some vegetable crops.

The key thing in Terra Preta is this fertility appears to be long lasting. Some of the Terra Preta soils are 1000 years old.

Clearly, we are in no position to prove our version will last this long. What we can say is that our type of biochar has been tested as stable for hundreds if not many hundreds of years. The early indications (noting our Solvita soil test setup is rudimentary) indicates the colloidal humus fraction is stable and will last for over 100 years. 

Why use our recipe/product to make your own Terra Preta?

There will be other recipes on the internet. Our recipe is based on significant expertise in biochar and composting. On testing, we found we could recreate the fertility and increased plant growth in the first season. Our product works within weeks of adding it to the soil.

We have test containers now into their 4th year of use - it's the same soil/compost mix today as year one.

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