Regenerative Cannabis Farming

Biochar in Agriculture

The crop looks good—deep green and perky, no drooping or yellowing, better than it has looked in years. This (2019) was the year we went "all in," using biochar as an amendment for every plant. Our farmer, Ingrid, says that despite the 100° heat, the only plants that need extra water are the ones in pots. Other than some cages tipped by wind, there hasn't been much for her to do, just watch them grow.

The “regenerative” label refers to farming that builds soil fertility, leading to higher nutrient density. Not coincidentally, regenerative farming also protects soil from erosion and builds up tremendous stores of organic material and water. This used to be called “organic” farming, but the FDA organic food standards that protect the public from false claims do not also protect the soil. “Regenerative” asserts the essential role of soil health in nutrition.

Biochar increases the water and nutrient holding capacity of soil. It does this by providing pore spaces (its own) and having a slightly polar chemistry to which water (a polar molecule) and nutrients (made of electrically charged ions) adhere, creating a film of water and nutrients on the pore surfaces. This is called "adsorption."

When it is first made, the pore surfaces are mostly empty. If char is placed in the soil in this condition, it will adsorb water and nutrients until it’s saturated, and plants in this soil will suffer in the meantime. To avoid this, standard practice is to inoculate or "charge" the charcoal beforehand. The best way is to "co-compost" it by mixing it in when a compost pile is started.

We did it a little differently. Instead of co-composting, Ingrid inoculated the char in spring in large perforated kiddie pools with worm casting tea, Dr. Earth, and tailings from cannabis oil extraction before putting it in the ground. (See photo in the Inoculation section of this website.)

In past years, we followed the recipe used by the locals for preparing planting holes: bone meal, rock phosphate, chicken manure, oyster shells, kelp meal and bat guano. Ingrid, who works as much by intuition as by science, decided that with biochar this wasn't necessary. Some new soil was brought in to make continuous beds in the native clay soil, but most terraces only needed compost, rotted chips and chicken manure. The plants were in the ground very early, in late May, because we opted for DNA sex testing.

Ingrid supplemented some plants with willow extract with kelp to stimulate root growth once, and all received compost tea throughout the vegetative stage (until the end of July). For root rot, powdery mildew and mold, Ingrid used a foliar application of Serenade, which also helps plants fix N and regulate pH.

The result is what you see in the photos. For those not familiar with outdoor cannabis farming, the flowers are just getting started, and if all goes well, they’ll be tall “colas” by October. The point being: biochar is helping.

One final note: Soil is a living community dependent on organic matter. Biochar does not replace organic matter, although they both retain water and nutrients by adsorption. Organic matter is the food for microorganisms, whereas nothing eats charcoal, which is why it stays in the soil for hundreds or thousands of years, performing the same functions. But for organic matter to persist, not only must it be added regularly, the soil must not be tilled. Tillage oxidizes soil organic matter, and it bears mentioning that this is exactly what leads to desertification. Biochar is not a magic bullet; it has to be used in concert with sustainable agricultural practices.