More and more people are showing interest in using Biochar as a soil amendment. Unlike the interest that Biochar is attracting, knowing how to apply it, how much of it to apply, and under what circumstances to apply it is not widely known or clearly understood. Just like NPK fertilizers or liming agents, Biochar too can have very negative impacts on your garden or crop when incorrectly applied.
To help you to make a more informed decision regarding your purchase of Biochar, we have outlined 4 tips that should help to clear up some of these unknowns.
Tip #1: Buy Biochar only in dry weight whenever possible
Biochar is hydrophilic, or in simple terms, has an affinity for water. It is said that Biochar can absorb water up to as much as ten times its weight. It can even absorb significant moisture when exposed to humid air!
How do you avoid buying Biochar with moisture in it? Buy it in dry weight. Michigan Biochar, for example, only sells Biochar products by the dry quart. Though there may be moisture in the Biochar product you buy from us, compensation in measurement is made to exclude its water content.
Tip #2: Test the quality of your Biochar with tap water
Biochar is dusty by nature. You will notice that by picking up a handful of Biochar, your hands will become covered by a black powder. It is this powder we want to do our test with. Here are the steps:
Step 1: Pick up a handful of Biochar, letting your hands become completely covered with the black powder.
Step 2: Rinse your hands under warm tap water. All of the powder should rinse off your hands without the use of soap. If it rinses off, you have a good quality Biochar.
What if I had to use soap to rinse the black powder off my hands? Does this mean that the product I have bought isnt Biochar? Not necessarily. Lesser quality biochars, can be somewhat greasy to the touch. The greasy matter is called mobile matter. This is a build-up of matter that remains on Biochar when the wood it was made from did not properly carbonize. Greasy Biochar is still useable but it may take a significantly longer time for it to work as compared with good or high quality Biochar.
Tip #3: Do not apply raw Biochar to your garden or crop land
As mentioned earlier, Biochar is like a sponge. It very aggressively absorbs water. Likewise, it can absorb nutrients or other constituents out of your soil. This could be good or it could be bad. It really depends on your situation.
Disadvantages to adding raw Biochar to your soil:
Because of its aggressive absorption characteristics, it will compete with your plants for water. Depending on the amount of Biochar applied, your plants could be deprived of enough water that they fail to produce as they normally would.
Biochar just as easily absorbs nutrients as it does water. Again, depending on the amount of Biochar applied, your plants could be deprived of many nutrients needed in order for them to thrive or even survive!
Application of enough Biochar could result in your garden becoming totally non-productive for one or more seasons until it can come back into balance.
Advantage to adding raw Biochar to your soil:
For the gardener and the farmer alike, raw Biochar can be applied to absorb excesses in your soil. For example, it could mop up excess fertilizers or salt build-up. Attempting to use Biochar in this way requires a deep understanding of how Biochar works. You should always seek assistance of a professional when attempting to go this route.
It is best to apply Biochar inoculated (combined) with compost. There are many reasons for this, which are covered in depth in our future article Why Inoculate Biochar with Compost? Bottom line, for Biochar to be garden-ready, it must be inoculated.
Tip #4: Know your soil
Adding Biochar/compost to a garden that is low in ph and nutrients are the most common reasons for application. An important aspect you need to know is that Biochar does have a liming effect, with a ph of 8 or so. If you have a concern about how this may affect your garden, you may want to do a soil test.
On the other hand, applying Biochar/compost to your low ph thriving plants might not have any negative affects at all. A friend of mine has been applying Biochar to his gardens for several years. He is also a consultant in the Biochar field. He has been applying Biochar compost to his blue berry plants (that prefer low ph soils). The yields have been great! He has concluded that ph levels, though important, are just a small part of the overall picture.
Biochar research is still in its infancy. Dont hesitate to experiment!
Case Study
Our farm (Back to Basic Living, LLC) in Wexford County in northern Michigan, is primarily a sandy loam, with an average ph of about 5.5. It hasnt been farmed for the better part of a century. For us, it was an easy choice. Apply a 50/50 mix of Biochar and compost. Continue adding this mixture, year after year until we have reached our goal of 10-15% Biochar by volume.
We have shown youtube studies on the effects of Biochar. Each year we will be expanding our studies in our gardens and will be sharing our video results with you.
One last thing
It is important to understand that these are just general rules. Each garden or crop is different based on its gardening/farming history, soil make-up and use of both organic and chemical fertilizers. If you are unsure as to how Biochar may affect your situation, you may want to try it in test plots.