If you’re reading this, first of all, good for you for being part of the biochar movement! Biochar does us no good when it is only in our heads—the real change happens as soon as you buy/make biochar and put it to use! So when you’re applying biochar to your soil, remember that while you are increasing your garden’s fertility, you are also sequestering carbon and becoming part of a global response to climate change! The carbon you are putting in your soil (biochar is mostly carbon!), will not return to the atmosphere as the greenhouse gas carbon dioxide for a very, very long time. But first, how do you apply biochar to the soil? It’s super simple, I promise!
(Feel free to check out my YouTube video that shows how to do this).
I’ve read a lot of scientific studies that have experimented with different application rates and how they affect plant growth. So many, in fact, that sometimes it’s hard to figure out how much to use! Factors like what kind of soil you have, what kind of biochar you’re using, or even how the biochar was made, affects how much to use. Considering all of these variables, it’s a safe bet to aim for 5% of the top 6 inches of soil to be biochar—this means if you’re using a 50/50 compost blend, aim for 10%. Just spread it on top of your soil and till it in! But remember that all soils are different, so feel free to experiment with application rates and let me know what you find! (email: firstname.lastname@example.org)
Why the top six inches? It turns out that this top layer of earth is the most biologically active area of soil. So when we boost the biology (BIO-char, right?) in that super-active layer, the results we see are much more significant than if we buried it two feet deep. These six inches encompass a critical zone where microbes and roots interact, nutrients are cycled, and many of the important soil processes take place; this is where the magic happens.
As you stand back to look at your freshly amended soil, give yourself a dirty pat on the back and a green-thumbs up for helping put carbon back in its place.
Be cool to the planet!
TL;DR –Shoot for 5% biochar in top six inches by tilling it in. Different soils have different needs so experiment with rates!