Note the step of adding it to your compost, not to your soil directly. The charcoal acts like a sponge for water soluble nutrients in the soil; if you add it t

Note the step of adding it to your compost, not to your soil directly. The charcoal acts like a sponge for water soluble nutrients in the soil; if you add it to the soil directly, it will suck them out of the soil first, temporarily depleting it. Long term it acts as a reservoir, but you want it to go into your garden full.