[svalli]

This may be out of the topic since I have not used biochar, but mixed wood ashes from our fireplace to my potting mix and flowerbeds to increase too low pH. There were some tiny charcoal pieces, but most was fine ash. Ashes seem to do wonders for my flowers, which looked much better than previous years. Container tomatoes and cucumbers look great too and no BER so far.

Farming methods in Finland used to be same as done by native Americans. People cut down the trees, burned them and mixed the ashes and charcoal to ground. They used to grow grain on that land two years and then couple of years of turnips and then move to an other area and let the trees grow back. This was done mainly on land, which was growing birches. That was the most common farming method here until the 19th century.