BioChar is a form of charcoal. Unlike the charcoal that you would use in a barbecue, BioChar is created, not mined. As such, carbon that would have gassed off into the atmosphere as CO2 is now being added back into the soil.
BioChar is created with a process that is called Pyrolysis. In short, you make organic matter so hot that is would catch fire, but you are doing it in an enclosed environment. This prevents oxygen from being available, therefore the organic compounds are driven off as a gas. All that is left behind afterwords is carbon in a very interesting form.
There is a microscopic porous structure to BioChar. The pores create a very large surface area for bacteria, organic and inorganic compounds, toxins and poisons to be stored in.
Bacteria will use that BioChar as a home and a place to store food, resist being washed away by water and to reproduce.
There are also bacteria and fungi that are said to be able to lock away toxins and poisons into the BioChar. This would essentially render them inert.
BioChar appears to provide the most benefit to your soil at a volume of 5-10%, ideally around 8%. If you are working the top 6 inches of your soil, 8% translates to 1 gallon of BioChar for every 25 square feet of garden bed.
The BioChar that you add to your soil will not be depleted in your lifetime. Once you reach your chosen percentage, from 5%-10%, you never have to add it again.
DO NOT add BioChar to your soil until you have “charged” it. BioChar really wants to fill its porous structure with whatever it can. The easiest thing for it to fill itself with is the nutrients that you plants need. BioChar can hold many times the amount of nutrients than your soil can. If you do this, you will cause you soil to be nutrient deficient, not good.
Do not despair, there is an easy way to avoid this. Here are a couple simple recommendations in the form of recipes.
-For a straight bacterial recipe, mix equal parts grass clippings and BioChar. Allow this mixture to mature/compost for about 2 months. Ensure that you grass clippings are not collected from an area that dogs and cats frequent. This recipe works great if mixed in the fall and allowed to do its thing over winter. Then add it to your soil before or during spring planting.
-For a bacterial and fungal recipe, mix equal parts worm castings and biochar, then toss in 5-10% of that volume of unbleached flower. As is, this is too dry for the bacteria and fungi to do their thing, but it is the perfect consistency to mix together thoroughly. So do that, then add just enough water to it that it is the consistency of a wrung out kitchen sponge. Cover to protect from sunlight and rain. This recipe only needs to sit for 2 weeks before being added to your soil.
-This is the most complex of the recipes, but is provides a lot of awesomeness for your garden.Mix 4 parts BioChar, 1 part rock dust, 1 part worm castings and 1/2 part unbleached flour. Mix, Moisten and cover as in the previous recipe. Again this recipe will be ready in 2 weeks.
-Finally here is the easiest recipe of all for those of you who own chickens. Just toss it in the coop. When you next clean out the coop, the BioChar will be ready to add to your soil.
If you go to purchase BioChar, you will find a very confusing price range from $1.50-$36 per gallon. Let’s cut through the confusion. $1.50 per gallon is plain unaltered BioChar. If you plan on following one of the recipes above, buy that. As the price goes up, generally the BioChar has been treated with more complex recipes. If you just want something to add to your garden without all of the fuss, then go for the more expensive options.
If you purchase BioChar in volumes less than 1 gallon, you will be paying way to much by volume for your BioChar. BioChar is available in 1 Cubic Foot bags. These bags are enough to amend 175 square feet of garden. 1 Cubic Foot bags are a very good option for the home/small gardener.
DO NOT, DO NOT, DO NOT buy BioChar that is sold by WEIGHT.
BioChar is extremely lightweight. When absolutely bone dry 1 gallon of BioChar will weigh less than 1 pound. At the same time, it is very easy for there to be 1 cup of excess moisture inside 1 gallon of BioChar. Guess what, now that BioChar weighs 2 pounds. If you were buying it in this scenario by weight, you would only get half as much.
If you are a Do It Yourselfer, BioChar is not difficult to make for yourself. This will be covered in a future article. Once it has been written, a link to it will be posted here.