Fungus. Microbes. Compost. Worm castings: These are some of the ingredients you might find in a living soil. They may be unpalatable to human tastes, but they’re great eats for cannabis plants.
In addition to reducing the need for extra nutrients, living soils can help you save money and mitigate risk, said Louis Miller, owner of Miller Soils, LLC. His Boulder, Colo.-based company specializes in soil blends that contain biochar, or carbon created by burning wood debris in the absence of oxygen.
And from what he’s seen, this breed of soil is gaining greater traction with large- and small-scale cannabis growers alike.
Technically, all soil is living soil—and a hardy kind, at that. “I don’t think that we can kill it,” said Woody Thorpe. He’s a certified crop advisor and owner of Insure Organics, a Valley Springs, Calif., company that provides soil inputs and biological products.
Soil attributes can be separated into three categories: chemical, physical and biological. The last of these “is the driving force of living soil,” Thorpe said.
The next time you’re out in nature, take a good look at the ground beneath your feet. What looks like plain dirt is actually a complex ecosystem comprised of organisms both within and above the soil. These include bacteria, fungus, yeasts and small microbes, as well as larger creatures like beetles and earthworms. Even surface-dwelling animals that deposit their own waste on the soil contribute to its rich biological profile, Thorpe said.
So why would you want living soil in your indoor grow? Simply put, a living soil is one that is “providing everything that the plant needs,” Miller said. “And in an ideal situation, the plant is reproducing everything that the plant needs.”
Biochar provides a home for fungal and microbe development in the soil. The result: Your plants require fewer additional nutrients. However, growers shouldn’t expect living soils to feed their indoor, potted crops indefinitely. At some point, the soil will need a little help from you.
“There are a lot of variables that go into how long soil will feed a plant,” Miller said. “And really it starts with container size. That’s something that a lot of people don’t talk about.”
Let’s say you have a young cannabis plant in a five-gallon container filled with living soil. Chances are, it will consume all the nutrients in the container before it’s reached maturity. The smaller the container, the quicker the plant will devour the nutrients, he said.
Living soils play a part in larger industry trends. Miller believes that as the cannabis industry grows, it will make sense for large-scale greenhouses to shift to soil-based growing. Soil can be recycled, which reduces costs, he said.
It can also help mitigate your risk. Compared to hydroponic growing, soils offer “a little less risk of catastrophic failure,” Miller said.
A shift toward organics and an increased awareness of sustainability issues are pushing living soils to the forefront. Soil is typically “a little more sustainable, and we’re starting to see people be more interested in being more sustainable, lowering their carbon footprint, and being aware of what the plant’s consuming—because people are consuming what the plants consume,” he said.
Biochar-enriched soils require less nutrients and water. “That alone is a huge step forward in sustainability in the cannabis industry,” Miller said.
Finally, living soils are quickly gaining traction among boutique growers, particularly those in Washington state and Colorado, he said. These growers are “going for a higher-end market share through growing organically,” he said.
A few simple steps will help you get more mileage out of your soil. Here are Thorpe’s suggestions:
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