Just like humans or animals will get sick without their immune systems, so will plants. Therefore, it’s critical that cannabis growers ensure their plants have healthy immune systems. But that creates a problem for many growers who believe that in a controlled environment, you have to use sterile grow media. The truth is inert media doesn’t include the biology your plants need to defend against pest and pathogens. No biology in the soil means no immune system for your plants. It’s that simple.