Biochar - Older Than You Think...

We’ve been stocking Biochar from a few different suppliers here at the shop for a little while, but we’ve never stopped to really figure out how or why it works. Turns out that it all goes back to indigenous settlers in the Amazon and the work of Dutch soil boffin Wim Sombroek. Who would've guessed?

The idea of Biochar comes from ‘Terra preta’, which is a black anthropogenic soil found in the Amazon basin, especially in Brasil, where Sombroek completed most of his research. Some studies suggest that these dark soils actually take up 150,000 square kilometres, which is 3.2% of the entire rainforest. So 3864 times the size of Waltham Forest.

 Within these soils, archaeologists have found traces of bone, pottery, compost, manure, and charcoal.   

It’s believed that the indigenous people of the Amazon would smoulder biomass by placing earth over burning agricultural waste. How they worked out that this would help plant growth is unknown, but we do know that when they mixed it with the other available substrates, it would boost what was otherwise weak soil for crop growing.

The addition of organic matter and broken pots etc was already a common process by the time these dark soils were fully examined. What did cause interest was the charcoal that made the ground so black. Upon investigation, scientists found that aside from improving soil structure, the charred biomass locks in carbon. This allows it to be taken out of the atmosphere and buried or sequestered into the ground indefinitely. In fact, over an area of 250–700 square kilometres the dark soils were found to sequester up to 3–7 megatons of extra carbon, when compared to any uninfluenced soil.

Sombroek recognised the importance of this and dedicated most of his professional life to bringing the Amazonian dark soils to the attention of the world through his research.

 This eventually led to scientists to burn biomass themselves using the process of pyrolysis, which burns fuel without the use of oxygen. This process allowed the mass production of what we now known as ‘biochar’.

In agricultural and horticultural settings, biochar becomes particularly useful in long term nutrient and water retention. It’s microscopic honeycomb structure helps to hold in nutrients from surrounding fertilisers and creates the perfect environment for microbes to breed and flourish; both of which are vital for root and plant growth. Also, as it biodegrades very slowly (think hundreds of years), it provides a near enough permanent way to improve soil structure, break up soils like clay and improve aeration.

If that wasn't enough, it takes on extra shifts helping the planet distribute and hideaway carbon, nifty stuff.

We’ve found that because biochar doesn’t contain any nutrients or fertilisers itself, you can use it across the garden or home, helping to improve what is already there or whatever you add. Whether that’s improving the soil that your Monstera sits in or making sure that new turf is going down on the best ground.

Carbon Gold, our main supplier of Biochar, demonstrate this by splitting their products into different use categories. This allows them to add fertilisers such as seaweed and growth stimulators like mycorrhizal fungi to match the application, whilst keeping biochar as the base.

So what you see in those nicely branded little tubs here in the shop or on our website actually has links back to one of the world's oldest civilizations. Talk about tried and tested...